Environmental Engineering 30 (Sullivan): Primary and Secondary Sources

Types of Sources

"Section 2: Knowledge Cycle" of The Research Process gives examples of primary, secondary, and tertiary sources.

UC Irvine: Introduction to Primary Sources
A basic explanation of what primary sources are, a description of the characteristics of primary sources, specific examples of primary sources, and an explanation of how primary sources differ from secondary and tertiary sources.
University of West Florida Libraries: Primary vs. Secondary Sources
Provides explanation and examples of primary sources.