?url_ver=Z39.88-2004&rft_id=10.1007%2F978-1-4757-1879-9_14&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Abook&rft.au=Keyfitz%2C+N.&rft.aulast=Keyfitz&rft.aufirst=N.&rft.date=1985&rft.issn=1431-875X&rft.isbn=978-1-4757-1879-9&rft.title=Heterogeneity+and+Selection+in+Population+Analysis&rft.btitle=Applied+Mathematical+Demography&rft.genre=bookitem