The text of this article is only available as a PDF.

References

Jaffe, A. J. 1971. The Middle Years. Special edition of Industrial Gerontology. September.
U. S. Census of Population: 1960
. (
1963
).
Washington, D. C.
:
U. S. Government Printing Office
.
U. S. Census of Population: 1970. Earnings by Occupation and Education
. (
1973
).
Washington, D. C.
:
U. S. Government Printing Office
.