APA (7th ed.) Citation

Opll, F. (2011). Regesta imperii. Regesta Imperii.

Chicago Style (17th ed.) Citation

Opll, Ferdinand. "Regesta Imperii." Regesta Imperii 2011.

MLA (9th ed.) Citation

Opll, Ferdinand. "Regesta Imperii." Regesta Imperii, 2011.

Warning: These citations may not always be 100% accurate.