← Search American Economic Review Vol. 75 No. 2 1985 New Evidence on the Timing and Spacing of Births James J. Heckman; V. Joseph Holtz; James R. Walker Volume75 Issue2 Pages179-184 Sources bibtex:phds-export.bib Cite APA 7 MLA 9 Chicago (author–date) Harvard Elsevier Harvard (JFE, JBF…) The Accounting Review Academy of Management American Marketing Association INFORMS (Management Science) Copy citation Copied ✓