APA
Krombein K. V., . (1958). Hymenoptera of america north of mexico synoptic catalog: agriculture monograph No-2 (united states department of agriculture). Washington: U.S. Government Printing Office.
Chicago
Krombein K V, . 1958. Hymenoptera of america north of mexico synoptic catalog: agriculture monograph No-2 (united states department of agriculture). Washington: U.S. Government Printing Office.
Harvard
Krombein K. V., . (1958). Hymenoptera of america north of mexico synoptic catalog: agriculture monograph No-2 (united states department of agriculture). Washington: U.S. Government Printing Office.
MLA
Krombein K V, . Hymenoptera of america north of mexico synoptic catalog: agriculture monograph No-2 (united states department of agriculture). Washington: U.S. Government Printing Office. 1958.