Walter, H. G., & Sovers, O. J. (2000). Astrometry of fundamental catalogues: The evolution from optical to radio reference frames. Berlin: Springer.
Παραπομπή Chicago StyleWalter, Hans G., and Ojars J. Sovers. Astrometry of Fundamental Catalogues: The Evolution From Optical to Radio Reference Frames. Berlin: Springer, 2000.
Παραπομπή MLAWalter, Hans G., and Ojars J. Sovers. Astrometry of Fundamental Catalogues: The Evolution From Optical to Radio Reference Frames. Berlin: Springer, 2000.
Πρόσοχή: Οι παραπομπές μπορεί να μην είναι 100% ακριβείς.