Cita APA (7a ed.)

Darwin, C. R., & Gray, A. The variation of animals and plants under domestication / by Charles Darwin, M. A., F.R.S., &c. ; authorized edition, with a preface by professor Asa Gray... With illustrations.

Cita Chicago Style (17a ed.)

Darwin, Charles Robert, y Asa Gray. The Variation of Animals and Plants Under Domestication / by Charles Darwin, M. A., F.R.S., &c. ; Authorized Edition, with a Preface by Professor Asa Gray... With Illustrations. New-York : Orange Judd & company, 245 Broadway, 18--.

Cita MLA (8a ed.)

Darwin, Charles Robert, y Asa Gray. The Variation of Animals and Plants Under Domestication / by Charles Darwin, M. A., F.R.S., &c. ; Authorized Edition, with a Preface by Professor Asa Gray... With Illustrations.