Cita APA (7a ed.)

Higgins, L. G., & Riley, N. D. (1970). A Field guide to the butterflies of Britain and Europe QL555 .A1 H. Collins.

Cita Chicago Style (17a ed.)

Higgins, Lionel George, y Norman Denbigh Riley. A Field Guide to the Butterflies of Britain and Europe QL555 .A1 H. London: Collins, 1970.

Cita MLA (9a ed.)

Higgins, Lionel George, y Norman Denbigh Riley. A Field Guide to the Butterflies of Britain and Europe QL555 .A1 H. Collins, 1970.