Cita APA (7th ed.)

Frè. (2013). Gravity, a Geometrical Course (1.). Springer Netherlands.

Cita Chicago (17th ed.)

Frè. Gravity, a Geometrical Course. 1. Springer Netherlands, 2013.

Cita MLA (8th ed.)

Frè. Gravity, a Geometrical Course. 1. Springer Netherlands, 2013.

Atenció: Aquestes cites poden no estar 100% correctes.