1971

June

1973

Spring

1977

April
May
June 
September

1979

April
Late Spring
Mid Summer 
Early Winter

1980

Spring
Early Winter
Late Winter 

1981

Summer
Undated, [circa 1981]
Late Winter

1982

Spring
Summer
September
Winter

1983

Spring
Summer 
Fall
Winter

1984

Autumn

1985

Summer
Letter to Subscribers, September 25, 1985

1989

Fall

1996

Summer