Cita APA (7th ed.)

Tyagi, B. S. (1985). Theory of Problems. Pragati Prakashan.

Cita Chicago (17th ed.)

Tyagi, B. S. Theory of Problems. Meerut: Pragati Prakashan, 1985.

Cita MLA (9th ed.)

Tyagi, B. S. Theory of Problems. Pragati Prakashan, 1985.