APA

Snow D. W., Snow B. K., .Relationships between hummingbirds and flowers in the Andes of Colombia. : .

Chicago

Snow David W, Snow Barbara K, .Relationships between hummingbirds and flowers in the Andes of Colombia. : .

Harvard

Snow D. W., Snow B. K., .Relationships between hummingbirds and flowers in the Andes of Colombia. : .

MLA

Snow David W, Snow Barbara K, .: . .