<P> Outlines are further differentiated by the index prefixing used, or lack thereof . Many outlines include a numerical or alphanumerical prefix preceding each entry in the outline, to provide a specific path for each item, to aid in referring to and discussing the entries listed . An alphanumerical outline uses alternating letters and numbers to identify entries . A decimal outline uses only numbers as prefixes . An outline without prefixes is called a "bare outline". </P> <P> Specialized applications of outlines also exist . A reverse outline is a list of sentences or topics that is created from an existing work, as a revision tool; it may show the gaps in the document's coverage so that they may be filled, and may help in rearranging sentences or topics to improve the structure and flow of the work . An integrated outline is a composition tool for writing scholastic works, in which the sources, and the writer's notes from the sources, are integrated into the outline for ease of reference during the writing process . </P> <P> A software program designed for processing outlines is called an outliner . </P> <P> Outlines are differentiated by style, the inclusion of prefixes, and specialized purpose . There are also hand - written outlines (which are highly limited in utility), and digitized outlines, such as those contained within an outliner (which are much more useful). </P>

A topic outline uses phrases for each entry