22
Nigg, Claudio R.
| The Gerontological Society of America |
1999
24
Verdi, Giuseppe
| Philps |
1984
25
Verdi, Giuseppe
| Philps |
1984
26
Ross, Robert R. N.
| Cambridge University Press:Harvard University Press |
1975
27
Ross, Robert A.
| University of Cincinnati |
2004