Issue #168 Nov 30, 1970 Issue #169 Jan 31, 1971 Issue #170 Mar 31, 1971 Issue #171 May 31, 1971 Issue #172 Jul 31, 1971 Issue #173 Aug 31, 1971 Issue #174 Issue #175 Oct 31, 1971 Issue #176 Issue #177 Issue #178 Issue #179 Issue #180 Mar 31, 1972 Issue #181 Apr 30, 1972 Issue #182 May 31, 1972 Issue #183 Jun 30, 1972 Issue #184 Jul 31, 1972 Issue #185 Aug 31, 1972 Issue #186 Sep 30, 1972 Issue #187 Oct 31, 1972