A secondary source is a second-hand account or interpretation, opinion, or analysis of an event. Good secondary sources are based on the interpretation of a wide variety of primary sources. Sometimes a source may contain both secondary and primary resource materials. Books, encyclopedias, scholarly and popular articles, textbooks, and statistics are examples of secondary sources.
A scholarly source is an article that is written by experts, for other experts in that discipline. Generally, scholarly sources are published in academic journals and books published by a university press.