(1990). Man and his environment: In harmony and in conflict. The Center for Humanities.
Chicago-referens (17:e uppl.)Man and His Environment: In Harmony and in Conflict. [S.l.]: The Center for Humanities, 1990.
MLA-referens (9:e uppl.)Man and His Environment: In Harmony and in Conflict. The Center for Humanities, 1990.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.