May-June 1967
July-August 1967
September-October 1967
November – December 1967
January – February 1968
March – April 1968
May – June 1968
July – August 1968
September – October 1968
November – December 1968
January – February 1969
March – April 1969
May – June 1969
July – August 1969
September – October 1969
November – December 1969