| Covers listed | |
| 1972: | December, |
| 1973: | May, September, December, |
| 1974: | February, May, September, December, |
| 1976: | December, |
| 1977: | February, |
| 1981: | Vol 11 # 4, |
| 1982: | Vol 12 # 3, |
| 1985: | Vol 15 # 4, |
| 1990: | Vol 20 # 1, |
| 1998: | Vol 28 # 1/2, |
| 1999: | Vol 29 # 1/2, Vol 29 # 3/4, |
| 2002: | Vol 32 No 1, Vol 32 No 2, Vol 32 # 2, |
| 2003: | Vol 33 # 1, |
