Serials are journals, periodicals, newspapers, annuals, etc., that appear in regular installments. ISSN=International Standard Serial Number, identifies a serial publication.
Digital library of academic journals, books, and primary sources, with a "moving wall" meaning the latest 3-5 years are NOT included.
Search for scholarly literature across many disciplines and sources: articles, theses, books, abstracts and court opinions, from academic publishers, professional societies, online repositories, universities and other web sites. [Google Scholar Settings Library links to Northwestern University - Find it @ NU (you can choose up to five libraries)]: