APA (7th ed.) Citation

Clette, F., Cugnon, P., & Gabryl, J. The program of the Royal Observatory of Belgium for the total solar eclipse of August 11th 1999.

Chicago Style (17th ed.) Citation

Clette, F., P. Cugnon, and J.-R Gabryl. The Program of the Royal Observatory of Belgium for the Total Solar Eclipse of August 11th 1999.

MLA (9th ed.) Citation

Clette, F., et al. The Program of the Royal Observatory of Belgium for the Total Solar Eclipse of August 11th 1999.