Cita APA (7a ed.)

Cumpa, J., & Tegtmeier, E. (2011). Ontological categories. Ontos Verlag.

Cita Chicago Style (17a ed.)

Cumpa, Javier, y Erwin Tegtmeier. Ontological Categories. Frankfurt: Ontos Verlag, 2011.

Cita MLA (9a ed.)

Cumpa, Javier, y Erwin Tegtmeier. Ontological Categories. Ontos Verlag, 2011.