Cita APA (7a ed.)

Payne-Gaposchkin, C., & Gaposchkin, S. (1938). Variable stars. Harvard Observatory.

Cita Chicago Style (17a ed.)

Payne-Gaposchkin, Cecilia, y Sergei Gaposchkin. Variable Stars. Cambridge: Harvard Observatory, 1938.

Cita MLA (9a ed.)

Payne-Gaposchkin, Cecilia, y Sergei Gaposchkin. Variable Stars. Harvard Observatory, 1938.