To locate articles in various periodicals , you should use at least one of the indexing and abstracting services listed below. In addition to the library resources, also use these often overlooked sources:
What is "gray literature"?
Gray literature is the term that is applied to sources of information that are not commercially published and are not generally available from bookstores, libraries, or traditional bibliographic sources. These works are often used to solicit constructive feedback from experts in the fields and are later published in peer-reviewed journals and other scholarly outlets. Gray literature includes: