APA (7th ed.) Citation

Bien, R., Fuchs, B., & Wielen, R. (1990). A simplified numerical treatment of encounters between galaxies. Dynamics and interactions of galaxies.

Chicago Style (17th ed.) Citation

Bien, Reinhold, Burkhard Fuchs, and Roland Wielen. "A Simplified Numerical Treatment of Encounters Between Galaxies." Dynamics and Interactions of Galaxies 1990.

MLA (9th ed.) Citation

Bien, Reinhold, et al. "A Simplified Numerical Treatment of Encounters Between Galaxies." Dynamics and Interactions of Galaxies, 1990.