Issue #520 Issue #521 Feb 14, 1974 Issue #522 Feb 28, 1974 Issue #523 Mar 14, 1974 Issue #524 Mar 28, 1974 Issue #525 Apr 11, 1974 Issue #526 Apr 25, 1974 Issue #527 May 09, 1974 Issue #528 May 23, 1974 Issue #529 Issue #530 Jun 18, 1974 Issue #531 Issue #532 Jul 16, 1974 Issue #533 Jul 30, 1974 Issue #534 Issue #535 Issue #536 Issue #537 Sep 14, 1974 Issue #538 Issue #539 Oct 12, 1974