Though abbreviations for such words as chapter (ch.), edition (ed.), page (p.), or pages (pp.) are common in source citations, they are not appropriate in the body of a formal academic text.

Place-names and months of the year are often abbreviated in source citations, but they should almost always be written out within sentences.

Common exceptions are Washington, DC, and U.S. The latter is acceptable as an adjective but not as a noun.

The U.S. delegation negotiated the treaty.