Cita APA

Pogorelov, A. V., Kra, I., & Zaustinskiy, E. (1979). Hilbert's fourth problem.

Citación estilo Chicago

Pogorelov, A. V., Irwin Kra, and Eugene Zaustinskiy. Hilbert's Fourth Problem. Washington, D.C, 1979.

Cita MLA

Pogorelov, A. V., et al. Hilbert's Fourth Problem. 1979.