APA (7th ed.) Citation

Bilt, J. v. d. (1908). The variable star U Geminorum. J. van Bockhoven.

Chicago Style (17th ed.) Citation

Bilt, J. van der. The Variable Star U Geminorum. Utrecht: J. van Bockhoven, 1908.

MLA (9th ed.) Citation

Bilt, J. van der. The Variable Star U Geminorum. J. van Bockhoven, 1908.