Cita APA (7a ed.)

Barnes, C. R., Norford, B. S., & Skevington, D. (1981). The ordovician system in Canadá: Correlation charts and explanatory notes. IUGS.

Cita Chicago Style (17a ed.)

Barnes, Christopher R., B. S. Norford, y David Skevington. The Ordovician System in Canadá: Correlation Charts and Explanatory Notes. Ottawa, Canadá: IUGS, 1981.

Cita MLA (8a ed.)

Barnes, Christopher R., et al. The Ordovician System in Canadá: Correlation Charts and Explanatory Notes. IUGS, 1981.