Richards, O. W. (1977). Hymenoptera : introduction and key to families / by O.W. Richards: Introduction and key to families (2nd ed.). Royal Entomological Society.
Chicago Style (17th ed.) CitationRichards, O. W. Hymenoptera : Introduction and Key to Families / by O.W. Richards: Introduction and Key to Families. 2nd ed. Royal Entomological Society, 1977.
MLA (9th ed.) CitationRichards, O. W. Hymenoptera : Introduction and Key to Families / by O.W. Richards: Introduction and Key to Families. 2nd ed. Royal Entomological Society, 1977.
Warning: These citations may not always be 100% accurate.