IDEAS home Printed from https://ideas.repec.org/p/iza/izadps/dp15609.html
   My bibliography  Save this paper

Analysis of Twins

Author

Listed:
  • Bhalotra, Sonia R.

    (University of Warwick)

  • Clarke, Damian

    (University of Chile)

Abstract

The occurrence of twin births has been widely used as a natural experiment. With a focus upon the use of twin births for identification of causal effects in economics, this chapter provides a critical review of methods and results.

Suggested Citation

  • Bhalotra, Sonia R. & Clarke, Damian, 2022. "Analysis of Twins," IZA Discussion Papers 15609, Institute of Labor Economics (IZA).
  • Handle: RePEc:iza:izadps:dp15609
    as

    Download full text from publisher

    File URL: https://docs.iza.org/dp15609.pdf
    Download Restriction: no
    ---><---

    Other versions of this item:

    References listed on IDEAS

    as
    1. Heather Royer, 2009. "Separated at Girth: US Twin Estimates of the Effects of Birth Weight," American Economic Journal: Applied Economics, American Economic Association, vol. 1(1), pages 49-85, January.
    2. Douglas Almond & Bhashkar Mazumder, 2013. "Fetal Origins and Parental Responses," Annual Review of Economics, Annual Reviews, vol. 5(1), pages 37-56, May.
    3. Kenneth I. Wolpin & Mark R. Rosenzweig, 2000. "Natural "Natural Experiments" in Economics," Journal of Economic Literature, American Economic Association, vol. 38(4), pages 827-874, December.
    4. Neumark, David, 1999. "Biases in twin estimates of the return to schooling," Economics of Education Review, Elsevier, vol. 18(2), pages 143-148, April.
    5. Mark R. Rosenzweig & Junsen Zhang, 2009. "Do Population Control Policies Induce More Human Capital Investment? Twins, Birth Weight and China's "One-Child" Policy," The Review of Economic Studies, Review of Economic Studies Ltd, vol. 76(3), pages 1149-1174.
    6. Braakmann, Nils & Wildman, John, 2014. "Fertility treatments and the use of twin births as an instrument for fertility," MPRA Paper 54106, University Library of Munich, Germany.
    7. Sonia Bhalotra & Damian Clarke, 2019. "Twin Birth and Maternal Condition," The Review of Economics and Statistics, MIT Press, vol. 101(5), pages 853-864, December.
    8. Jere R. Behrman & Mark R. Rosenzweig, 2002. "Does Increasing Women's Schooling Raise the Schooling of the Next Generation?," American Economic Review, American Economic Association, vol. 92(1), pages 323-334, March.
    9. Miller, Paul & Mulvey, Charles & Martin, Nick, 2005. "Birth weight and schooling and earnings: estimates from a sample of twins," Economics Letters, Elsevier, vol. 86(3), pages 387-392, March.
    10. Douglas Almond & Lena Edlund & Mårten Palme, 2009. "Chernobyl's Subclinical Legacy: Prenatal Exposure to Radioactive Fallout and School Outcomes in Sweden," The Quarterly Journal of Economics, President and Fellows of Harvard College, vol. 124(4), pages 1729-1772.
    11. Sandra E. Black & Paul J. Devereux & Kjell G. Salvanes, 2007. "From the Cradle to the Labor Market? The Effect of Birth Weight on Adult Outcomes," The Quarterly Journal of Economics, President and Fellows of Harvard College, vol. 122(1), pages 409-439.
    12. Behrman, Jere R & Rosenzweig, Mark R & Taubman, Paul, 1996. "College Choice and Wages: Estimates Using Data on Female Twins," The Review of Economics and Statistics, MIT Press, vol. 78(4), pages 672-685, November.
    13. Henrik Kleven & Camille Landais & Jakob Egholt Søgaard, 2019. "Children and Gender Inequality: Evidence from Denmark," American Economic Journal: Applied Economics, American Economic Association, vol. 11(4), pages 181-209, October.
    14. Sandewall, Örjan & Cesarini, David & Johannesson, Magnus, 2014. "The co-twin methodology and returns to schooling — testing a critical assumption," Labour Economics, Elsevier, vol. 26(C), pages 1-10.
    15. Vladimir Ponczek & Andre Portela Souza, 2012. "New Evidence of the Causal Effect of Family Size on Child Quality in a Developing Country," Journal of Human Resources, University of Wisconsin Press, vol. 47(1), pages 64-106.
    16. repec:bla:econom:v:64:y:1997:i:253:p:119-36 is not listed on IDEAS
    17. Kenneth Y. Chay & Michael Greenstone, 2003. "The Impact of Air Pollution on Infant Mortality: Evidence from Geographic Variation in Pollution Shocks Induced by a Recession," The Quarterly Journal of Economics, President and Fellows of Harvard College, vol. 118(3), pages 1121-1167.
    18. Bound, John & Solon, Gary, 1999. "Double trouble: on the value of twins-based estimation of the return to schooling," Economics of Education Review, Elsevier, vol. 18(2), pages 169-182, April.
    19. Rosenzweig, Mark R & Wolpin, Kenneth I, 1980. "Testing the Quantity-Quality Fertility Model: The Use of Twins as a Natural Experiment," Econometrica, Econometric Society, vol. 48(1), pages 227-240, January.
    20. Philip Oreopoulos & Mark Stabile & Randy Walld & Leslie L. Roos, 2008. "Short-, Medium-, and Long-Term Consequences of Poor Infant Health: An Analysis Using Siblings and Twins," Journal of Human Resources, University of Wisconsin Press, vol. 43(1).
    21. David Figlio & Jonathan Guryan & Krzysztof Karbownik & Jeffrey Roth, 2014. "The Effects of Poor Neonatal Health on Children's Cognitive Development," American Economic Review, American Economic Association, vol. 104(12), pages 3921-3955, December.
    22. Mogstad, M. & Wiswall, M., 2012. "Instrumental variables estimation with partially missing instruments," Economics Letters, Elsevier, vol. 114(2), pages 186-189.
    23. Vikesh Amin & Jere Behrman, 2014. "Do more-schooled women have fewer children and delay childbearing? Evidence from a sample of US twins," Journal of Population Economics, Springer;European Society for Population Economics, vol. 27(1), pages 1-31, January.
    24. Bhalotra, Sonia & Clarke, Damian & Mühlrad, Hanna & Palme, Mårten, 2021. "Health and Labor Market Impacts of Twin Birth : Evidence from a Swedish IVF Policy Mandate," The Warwick Economics Research Paper Series (TWERPS) 1391, University of Warwick, Department of Economics.
    25. Hanushek, Eric A, 1992. "The Trade-Off between Child Quantity and Quality," Journal of Political Economy, University of Chicago Press, vol. 100(1), pages 84-117, February.
    26. Savelyev, Peter A. & Ward, Benjamin C. & Krueger, Robert F. & McGue, Matt, 2022. "Health endowments, schooling allocation in the family, and longevity: Evidence from US twins," Journal of Health Economics, Elsevier, vol. 81(C).
    27. Dinand Webbink & Pierre Koning & Sunčica Vujić & Nicholas G. Martin, 2013. "Why Are Criminals Less Educated than Non-Criminals? Evidence from a Cohort of Young Australian Twins," The Journal of Law, Economics, and Organization, Oxford University Press, vol. 29(1), pages 115-144, February.
    28. Berniell, Inés & Berniell, Lucila & Mata, Dolores de la & Edo, María & Marchionni, Mariana, 2021. "Gender gaps in labor informality: The motherhood effect," Journal of Development Economics, Elsevier, vol. 150(C).
    29. Douglas Almond & Kenneth Y. Chay & David S. Lee, 2005. "The Costs of Low Birth Weight," The Quarterly Journal of Economics, President and Fellows of Harvard College, vol. 120(3), pages 1031-1083.
    30. Angrist, Joshua D & Evans, William N, 1998. "Children and Their Parents' Labor Supply: Evidence from Exogenous Variation in Family Size," American Economic Review, American Economic Association, vol. 88(3), pages 450-477, June.
    31. Miller, Paul W & Mulvey, Charles & Martin, Nick, 1995. "What Do Twins Studies Reveal about the Economic Returns to Education? A Comparison of Australian and U.S. Findings," American Economic Review, American Economic Association, vol. 85(3), pages 586-599, June.
    32. Jere Behrman & Hans-Peter Kohler & Vibeke Jensen & Dorthe Pedersen & Inge Petersen & Paul Bingley & Kaare Christensen, 2011. "Does More Schooling Reduce Hospitalization and Delay Mortality? New Evidence Based on Danish Twins," Demography, Springer;Population Association of America (PAA), vol. 48(4), pages 1347-1375, November.
    33. Behrman, Jere R & Taubman, Paul, 1989. "Is Schooling "Mostly in the Genes"? Nature-N urture Decomposition Using Data on Relatives," Journal of Political Economy, University of Chicago Press, vol. 97(6), pages 1425-1446, December.
    34. James P. Vere, 2011. "Fertility and parents' labour supply: new evidence from US census data," Oxford Economic Papers, Oxford University Press, vol. 63(2), pages 211-231, April.
    35. Dinand Webbink & Nicholas Martin & Peter Visscher, 2011. "Does teenage childbearing reduce investment in human capital?," Journal of Population Economics, Springer;European Society for Population Economics, vol. 24(2), pages 701-730, April.
    36. Meltem Dayioğlu & Murat G. Kirdar & Aysit Tansel, 2009. "Impact of Sibship Size, Birth Order and Sex Composition on School Enrolment in Urban Turkey," Oxford Bulletin of Economics and Statistics, Department of Economics, University of Oxford, vol. 71(3), pages 399-426, June.
    37. Amin, Vikesh & Behrman, Jere R. & Kohler, Hans-Peter, 2015. "Schooling has smaller or insignificant effects on adult health in the US than suggested by cross-sectional associations: New estimates using relatively large samples of identical twins," Social Science & Medicine, Elsevier, vol. 127(C), pages 181-189.
    38. Jere R. Behrman & Mark R. Rosenzweig, 2004. "Returns to Birthweight," The Review of Economics and Statistics, MIT Press, vol. 86(2), pages 586-601, May.
    39. Miller, Paul & Mulvey, Charles & Martin, Nick, 2006. "The return to schooling: Estimates from a sample of young Australian twins," Labour Economics, Elsevier, vol. 13(5), pages 571-587, October.
    40. Martin Eckhoff Andresen & Emily Nix, 2022. "What Causes the Child Penalty? Evidence from Adopting and Same-Sex Couples," Journal of Labor Economics, University of Chicago Press, vol. 40(4), pages 971-1004.
    41. Åslund, Olof & Grönqvist, Hans, 2010. "Family size and child outcomes: Is there really no trade-off?," Labour Economics, Elsevier, vol. 17(1), pages 130-139, January.
    42. Mark E. McGovern, 2019. "How much does birth weight matter for child health in developing countries? Estimates from siblings and twins," Health Economics, John Wiley & Sons, Ltd., vol. 28(1), pages 3-22, January.
    43. Dalton Conley & Kate Strully & Neil G. Bennett, 2003. "A Pound of Flesh or Just Proxy? Using Twin Differences to Estimate the Effect of Birth Weight on Life Chances," NBER Working Papers 9901, National Bureau of Economic Research, Inc.
    44. Ashenfelter, Orley & Krueger, Alan B, 1994. "Estimates of the Economic Returns to Schooling from a New Sample of Twins," American Economic Review, American Economic Association, vol. 84(5), pages 1157-1173, December.
    45. Joyce P. Jacobsen & James Wishart Pearce III & Joshua L. Rosenbloom, 1999. "The Effects of Childbearing on Married Women's Labor Supply and Earnings: Using Twin Births as a Natural Experiment," Journal of Human Resources, University of Wisconsin Press, vol. 34(3), pages 449-474.
    46. Petter Lundborg & Erik Plug & Astrid Würtz Rasmussen, 2017. "Can Women Have Children and a Career? IV Evidence from IVF Treatments," American Economic Review, American Economic Association, vol. 107(6), pages 1611-1637, June.
    47. Orley Ashenfelter & Cecilia Rouse, 1998. "Income, Schooling, and Ability: Evidence from a New Sample of Identical Twins," The Quarterly Journal of Economics, President and Fellows of Harvard College, vol. 113(1), pages 253-284.
    48. Behrman, Jere R & Rosenzweig, Mark R & Taubman, Paul, 1994. "Endowments and the Allocation of Schooling in the Family and in the Marriage Market: The Twins Experiment," Journal of Political Economy, University of Chicago Press, vol. 102(6), pages 1131-1174, December.
    49. Petter Lundborg & Anton Nilsson & Dan-Olof Rooth, 2016. "The health-schooling relationship: evidence from Swedish twins," Journal of Population Economics, Springer;European Society for Population Economics, vol. 29(4), pages 1191-1215, October.
    50. Nils Braakmann & John Wildman, 2016. "Reconsidering the effect of family size on labour supply: the twin problems of the twin birth instrument," Journal of the Royal Statistical Society Series A, Royal Statistical Society, vol. 179(4), pages 1093-1115, October.
    51. Sandra E. Black & Paul J. Devereux & Kjell G. Salvanes, 2005. "The More the Merrier? The Effect of Family Size and Birth Order on Children's Education," The Quarterly Journal of Economics, President and Fellows of Harvard College, vol. 120(2), pages 669-700.
    52. Behrman, Jere R. & Xiong, Yanyan & Zhang, Junsen, 2015. "Cross-sectional schooling-health associations misrepresented causal schooling effects on adult health and health-related behaviors: Evidence from the Chinese Adults Twins Survey," Social Science & Medicine, Elsevier, vol. 127(C), pages 190-197.
    53. Petter Lundborg, 2013. "The health returns to schooling—what can we learn from twins?," Journal of Population Economics, Springer;European Society for Population Economics, vol. 26(2), pages 673-701, April.
    54. Henrik Cronqvist & Stephan Siegel, 2015. "The Origins of Savings Behavior," Journal of Political Economy, University of Chicago Press, vol. 123(1), pages 123-169.
    55. Böckerman, Petri & Maczulskij, Terhi, 2016. "The Education-health Nexus: Fact and fiction," Social Science & Medicine, Elsevier, vol. 150(C), pages 112-116.
    56. Behrman, Jere R & Taubman, Paul, 1976. "Intergenerational Transmission of Income and Wealth," American Economic Review, American Economic Association, vol. 66(2), pages 436-440, May.
    57. Rouse, Cecilia Elena, 1999. "Further estimates of the economic return to schooling from a new sample of twins," Economics of Education Review, Elsevier, vol. 18(2), pages 149-157, April.
    58. Junjian Yi & James J. Heckman & Junsen Zhang & Gabriella Conti, 2015. "Early Health Shocks, Intra†household Resource Allocation and Child Outcomes," Economic Journal, Royal Economic Society, vol. 125(588), pages 347-371, November.
    59. Gunnar Isacsson, 2004. "Estimating the economic return to educational levels using data on twins," Journal of Applied Econometrics, John Wiley & Sons, Ltd., vol. 19(1), pages 99-119.
    60. Joshua Angrist & Victor Lavy & Analia Schlosser, 2010. "Multiple Experiments for the Causal Link between the Quantity and Quality of Children," Journal of Labor Economics, University of Chicago Press, vol. 28(4), pages 773-824, October.
    61. Amin, Vikesh & Lundborg, Petter & Rooth, Dan-Olof, 2011. "Mothers Do Matter: New Evidence on the Effect of Parents' Schooling on Children's Schooling Using Swedish Twin Data," IZA Discussion Papers 5946, Institute of Labor Economics (IZA).
    62. Magne Mogstad & Matthew Wiswall, 2016. "Testing the quantity–quality model of fertility: Estimation using unrestricted family size models," Quantitative Economics, Econometric Society, vol. 7(1), pages 157-192, March.
    63. Conley, Dalton & Strully, Kate W. & Bennett, Neil G., 2006. "Twin differences in birth weight: The effects of genotype and prenatal environment on neonatal and post-neonatal mortality," Economics & Human Biology, Elsevier, vol. 4(2), pages 151-183, June.
    64. Bronars, Stephen G & Grogger, Jeff, 1994. "The Economic Consequences of Unwed Motherhood: Using Twin Births as a Natural Experiment," American Economic Review, American Economic Association, vol. 84(5), pages 1141-1156, December.
    65. Mary A. Silles, 2016. "The impact of children on women’s labour supply and earnings in the UK: evidence using twin births," Oxford Economic Papers, Oxford University Press, vol. 68(1), pages 197-216.
    66. Zhang, Junchao, 2017. "A dilemma of fertility and female labor supply: Identification using Taiwanese twins," China Economic Review, Elsevier, vol. 43(C), pages 47-63.
    67. Amin, Vikesh & Behrman, Jere R. & Spector, Tim D., 2013. "Does more schooling improve health outcomes and health related behaviors? Evidence from U.K. twins," Economics of Education Review, Elsevier, vol. 35(C), pages 134-148.
    68. Martin Kolk, 2015. "The causal effect of an additional sibling on completed fertility: An estimation of intergenerational fertility correlations by looking at siblings of twins," Demographic Research, Max Planck Institute for Demographic Research, Rostock, Germany, vol. 32(51), pages 1409-1420.
    69. Prashant Bharadwaj & Juan Pedro Eberhard & Christopher A. Neilson, 2018. "Health at Birth, Parental Investments, and Academic Outcomes," Journal of Labor Economics, University of Chicago Press, vol. 36(2), pages 349-394.
    70. Letícia Marteleto & Laetícia Souza, 2012. "The Changing Impact of Family Size on Adolescents’ Schooling: Assessing the Exogenous Variation in Fertility Using Twins in Brazil," Demography, Springer;Population Association of America (PAA), vol. 49(4), pages 1453-1477, November.
    71. Sandra E. Black & Paul J. Devereux & Kjell G. Salvanes, 2016. "Does Grief Transfer across Generations? Bereavements during Pregnancy and Child Outcomes," American Economic Journal: Applied Economics, American Economic Association, vol. 8(1), pages 193-223, January.
    72. Behrman, Jere R. & Rosenzweig, Mark R., 1999. ""Ability" biases in schooling returns and twins: a test and new estimates," Economics of Education Review, Elsevier, vol. 18(2), pages 159-167, April.
    73. repec:ucn:wpaper:10197/317 is not listed on IDEAS
    Full references (including those not matched with items on IDEAS)

    Most related items

    These are the items that most often cite the same works as this one and are cited by the same works as this one.
    1. Savelyev, Peter A. & Ward, Benjamin C. & Krueger, Robert F. & McGue, Matt, 2022. "Health endowments, schooling allocation in the family, and longevity: Evidence from US twins," Journal of Health Economics, Elsevier, vol. 81(C).
    2. Mark E. McGovern, 2019. "How much does birth weight matter for child health in developing countries? Estimates from siblings and twins," Health Economics, John Wiley & Sons, Ltd., vol. 28(1), pages 3-22, January.
    3. Petter Lundborg & Carl Hampus Lyttkens & Paul Nystedt, 2016. "The Effect of Schooling on Mortality: New Evidence From 50,000 Swedish Twins," Demography, Springer;Population Association of America (PAA), vol. 53(4), pages 1135-1168, August.
    4. Sonia Bhalotra & Damian Clarke, 2019. "Twin Birth and Maternal Condition," The Review of Economics and Statistics, MIT Press, vol. 101(5), pages 853-864, December.
    5. Sandewall, Örjan & Cesarini, David & Johannesson, Magnus, 2014. "The co-twin methodology and returns to schooling — testing a critical assumption," Labour Economics, Elsevier, vol. 26(C), pages 1-10.
    6. Lång, Elisabeth & Nystedt, Paul, 2016. "Learning For Life? The Effects of Schooling on Earnings and Health- Related Behavior Over the Life Cycle," LiU Working Papers in Economics 4, Linköping University, Division of Economics, Department of Management and Engineering.
    7. Petter Lundborg & Anton Nilsson & Dan-Olof Rooth, 2016. "The health-schooling relationship: evidence from Swedish twins," Journal of Population Economics, Springer;European Society for Population Economics, vol. 29(4), pages 1191-1215, October.
    8. Brandon J. Restrepo, 2016. "Parental investment responses to a low birth weight outcome: who compensates and who reinforces?," Journal of Population Economics, Springer;European Society for Population Economics, vol. 29(4), pages 969-989, October.
    9. Vikesh Amin & Jere Behrman, 2014. "Do more-schooled women have fewer children and delay childbearing? Evidence from a sample of US twins," Journal of Population Economics, Springer;European Society for Population Economics, vol. 27(1), pages 1-31, January.
    10. Damian Clarke, 2018. "Children And Their Parents: A Review Of Fertility And Causality," Journal of Economic Surveys, Wiley Blackwell, vol. 32(2), pages 518-540, April.
    11. Jere Behrman & Hans-Peter Kohler & Vibeke Jensen & Dorthe Pedersen & Inge Petersen & Paul Bingley & Kaare Christensen, 2011. "Does More Schooling Reduce Hospitalization and Delay Mortality? New Evidence Based on Danish Twins," Demography, Springer;Population Association of America (PAA), vol. 48(4), pages 1347-1375, November.
    12. Semih Tumen & Belgi Turan, 2023. "The effect of fertility on female labor supply in a labor market with extensive informality," Empirical Economics, Springer, vol. 65(4), pages 1855-1894, October.
    13. Schultz, T. Paul, 2010. "Population and Health Policies," Handbook of Development Economics, in: Dani Rodrik & Mark Rosenzweig (ed.), Handbook of Development Economics, edition 1, volume 5, chapter 0, pages 4785-4881, Elsevier.
    14. Sandra E. Black & Paul J. Devereux & Kjell G. Salvanes, 2010. "Small Family, Smart Family? Family Size and the IQ Scores of Young Men," Journal of Human Resources, University of Wisconsin Press, vol. 45(1).
    15. Yusuf Sofiyandi1, 2018. "The Effect of Residential Location and Housing Unit Characteristics on Labor Force Participation of Childbearing Women in Indonesia: Using Twin Births As A Quasi-Natural Experiment," LPEM FEBUI Working Papers 201822, LPEM, Faculty of Economics and Business, University of Indonesia, revised Jul 2018.
    16. Almond, Douglas & Currie, Janet, 2011. "Human Capital Development before Age Five," Handbook of Labor Economics, in: O. Ashenfelter & D. Card (ed.), Handbook of Labor Economics, edition 1, volume 4, chapter 15, pages 1315-1486, Elsevier.
    17. Joshua Angrist & Victor Lavy & Analia Schlosser, 2010. "Multiple Experiments for the Causal Link between the Quantity and Quality of Children," Journal of Labor Economics, University of Chicago Press, vol. 28(4), pages 773-824, October.
    18. Guo, Rufei & Lin, Lin & Yi, Junjian & Zhang, Junsen, 2020. "The cross-spousal effect of education on health," Journal of Development Economics, Elsevier, vol. 146(C).
    19. Maruyama, Shiko & Heinesen, Eskil, 2020. "Another look at returns to birthweight," Journal of Health Economics, Elsevier, vol. 70(C).
    20. Miller, Paul & Mulvey, Charles & Martin, Nick, 2001. "Genetic and environmental contributions to educational attainment in Australia," Economics of Education Review, Elsevier, vol. 20(3), pages 211-224, June.

    More about this item

    Keywords

    fertility; birth spacing; child development; women's labour market outcomes; identification; twins; child penalty;
    All these keywords.

    JEL classification:

    • D10 - Microeconomics - - Household Behavior - - - General
    • I26 - Health, Education, and Welfare - - Education - - - Returns to Education
    • J13 - Labor and Demographic Economics - - Demographic Economics - - - Fertility; Family Planning; Child Care; Children; Youth
    • J24 - Labor and Demographic Economics - - Demand and Supply of Labor - - - Human Capital; Skills; Occupational Choice; Labor Productivity

    NEP fields

    This paper has been announced in the following NEP Reports:

    Statistics

    Access and download statistics

    Corrections

    All material on this site has been provided by the respective publishers and authors. You can help correct errors and omissions. When requesting a correction, please mention this item's handle: RePEc:iza:izadps:dp15609. See general information about how to correct material in RePEc.

    If you have authored this item and are not yet registered with RePEc, we encourage you to do it here. This allows to link your profile to this item. It also allows you to accept potential citations to this item that we are uncertain about.

    If CitEc recognized a bibliographic reference but did not link an item in RePEc to it, you can help with this form .

    If you know of missing items citing this one, you can help us creating those links by adding the relevant references in the same way as above, for each refering item. If you are a registered author of this item, you may also want to check the "citations" tab in your RePEc Author Service profile, as there may be some citations waiting for confirmation.

    For technical questions regarding this item, or to correct its authors, title, abstract, bibliographic or download information, contact: Holger Hinte (email available below). General contact details of provider: https://edirc.repec.org/data/izaaade.html .

    Please note that corrections may take a couple of weeks to filter through the various RePEc services.

    IDEAS is a RePEc service. RePEc uses bibliographic data supplied by the respective publishers.