APA

Gertler P. E., .Birds of the cave of the oilbirds national park, Huila, Colombia. : .

Chicago

Gertler Paul E, .Birds of the cave of the oilbirds national park, Huila, Colombia. : .

Harvard

Gertler P. E., .Birds of the cave of the oilbirds national park, Huila, Colombia. : .

MLA

Gertler Paul E, .: . .