Cita APA (7th ed.)

Spanier, E. H. (1966). Obstruction theory. IMPA-CNPq.

Cita Chicago (17th ed.)

Spanier, E. H. Obstruction Theory. Río de Janeiro: IMPA-CNPq, 1966.

Cita MLA (9th ed.)

Spanier, E. H. Obstruction Theory. IMPA-CNPq, 1966.