The seventh edition of the "MLA Handbook for Writers of Research Papers" provides guidelines for the liberal arts and humanities. The handbook covers a wide variety of citations, including government sources such as the Internal Revenue Service. The IRS has many materials to use as references.
When IRS information is included in the text, put a citation inside parentheses. Use the department's full name and the document's page number after the pertinent material, such as: (Internal Revenue Service 5). If the department's name is included in the text, omit it from the parentheses.
When an IRS document is cited in the text, include it on the Works Cited page. Begin with "U.S. Department of the Treasury, Internal Revenue Service" without quotation marks. Follow this with a period. Underline the title of the document, and add a period. Include "IRS Pub." without quotation marks and the document number. Add another period. For publication information, list "Washington: GPO" without quotation marks. Add a comma and the publication year. Finish with a period; for example: U. S. Department of the Treasury, Internal Revenue Service. Your Rights as a Taxpayer. IRS Pub. 1. Washington: GPO, 2012.