एपीए उद्धरण

Engel, A. (1998). Problem-solving strategies. Springer.

शिकागो स्टाइल उद्धरण

Engel, Arthur. Problem-solving Strategies. New Delhi: Springer, 1998.

एमएलए उद्धरण

Engel, Arthur. Problem-solving Strategies. Springer, 1998.