APA

Klots A. B., . (1969). A field guide to the butterflies of North America, East of the great plains. Cambridge: Houghton Mifflin Company Boston.

Chicago

Klots Alexander B, . 1969. A field guide to the butterflies of North America, East of the great plains. Cambridge: Houghton Mifflin Company Boston.

Harvard

Klots A. B., . (1969). A field guide to the butterflies of North America, East of the great plains. Cambridge: Houghton Mifflin Company Boston.

MLA

Klots Alexander B, . A field guide to the butterflies of North America, East of the great plains. Cambridge: Houghton Mifflin Company Boston. 1969.