APA (7th ed.) Citation
Gratian, a. 1. c., Thompson, A., Gordley, J., & Christensen, K. (1993). The treatise on laws: (Decretum DD. 1-20). Catholic University of America Press.
Chicago Style (17th ed.) Citation
Gratian, active 12th century, Augustine Thompson, James Gordley, and Katherine Christensen. The Treatise on Laws: (Decretum DD. 1-20). Washington, District of Columbia: Catholic University of America Press, 1993.
MLA (9th ed.) Citation
Gratian, active 12th century, et al. The Treatise on Laws: (Decretum DD. 1-20). Catholic University of America Press, 1993.
Warning: These citations may not always be 100% accurate.