John R Rohrbach Rohrbaugh 1728 1821 PDF Download

This "work is organized by subject. Materials are grouped under twelve main sections in the body of the work, with appropriate subdivisions and subtopics within each main subject. Each section is assigned a two-letter designation, and entries are numbered consecutively within each section. This subject code system was designed to facilitate referals from the Index to the main body of the text, and to allow for cross-referencing between sections."--Introduction.