Cita APA (7th ed.)

Gutierrez Vidalón, C. T., & Sotomayor Tello, J. (1991). Lines of curvature and umbilical points on surfaces. IMPA.

Cita Chicago (17th ed.)

Gutierrez Vidalón, Carlos Teobaldo, i Jorge Sotomayor Tello. Lines of Curvature and Umbilical Points on Surfaces. Río de Janeiro: IMPA, 1991.

Cita MLA (9th ed.)

Gutierrez Vidalón, Carlos Teobaldo, i Jorge Sotomayor Tello. Lines of Curvature and Umbilical Points on Surfaces. IMPA, 1991.