APA (7th ed.) Citation

Hirt, C., Burki, B., & Hirt, C. (2006). Status of Geodetic Astronomy at the Beginning of the 21st Century. University of Hanover.

Chicago Style (17th ed.) Citation

Hirt, Christian, B. Burki, and C. Hirt. Status of Geodetic Astronomy at the Beginning of the 21st Century. University of Hanover, 2006.

MLA (9th ed.) Citation

Hirt, Christian, et al. Status of Geodetic Astronomy at the Beginning of the 21st Century. University of Hanover, 2006.