Cita APA (7th ed.)

Pflugfelder, H. O. (1990). Quasigroups and loops: Introduction. Heldermann Verlag.

Cita Chicago (17th ed.)

Pflugfelder, Hala O. Quasigroups and Loops: Introduction. Berlín: Heldermann Verlag, 1990.

Cita MLA (9th ed.)

Pflugfelder, Hala O. Quasigroups and Loops: Introduction. Heldermann Verlag, 1990.