The Chicago Manual of Style includes two slightly different documentation systems: (1) notes and bibliography (NB) and (2) author-date. The notes and bibliography style is preferred by many in literature, history, and the arts.
In the NB system, you mark within your paper where you have cited something by adding a number, which refers to a detailed reference either at the bottom of the page (footnote) or at the end of the paper (endnote). These notes indicate the specific place in your source you are referencing.
The bibliography includes complete information for each item, with the items arranged in alphabetical order by author's last name.
Purdue's Writing Lab provides an example of a paper formatted using Chicago NB style.
Citation managers (also called reference managers or bibliographic management software) offer a way to save, organize and manage references. Many work with word processing software to format in-text citations and bibliographies for papers and theses, allow you to share references, and enable you to attach or link PDFs to a citation record.
Wikipedia comparison of reference management software