United States. Entomology Research Division & Krombein, K. V. Hymenoptera of America north of Mexico, synoptic catalog, first supplement.
Chicago Style (17th ed.) CitationUnited States. Entomology Research Division and Karl V. Krombein. Hymenoptera of America North of Mexico, Synoptic Catalog, First Supplement.
MLA (9th ed.) CitationUnited States. Entomology Research Division and Karl V. Krombein. Hymenoptera of America North of Mexico, Synoptic Catalog, First Supplement.
Warning: These citations may not always be 100% accurate.