Cita APA (7a ed.)

Gosler, A., Gosler, A., & Perrins, C. (1987). Some aspects of bill morphology in relation to ecology in the great tit Parus major.

Cita Chicago Style (17a ed.)

Gosler, A., Andrew Gosler, y C. Perrins. Some Aspects of Bill Morphology in Relation to Ecology in the Great Tit Parus Major. 1987.

Cita MLA (9a ed.)

Gosler, A., et al. Some Aspects of Bill Morphology in Relation to Ecology in the Great Tit Parus Major. 1987.