Created by the Modern Language Association, MLA is most commonly used in the liberal arts and humanities. The eighth edition of the MLA Handbook was published in August 2016. You may also want to use the free online MLA Style Center.
What happened to the The MLA Style Manual and Guide to Scholarly Publishing?
This publication is now out of print. According to the MLA website, "The system of documentation explained in the eighth edition of the MLA Handbook is the authoritative source for MLA style as of April 2016. The MLA is developing additional publications to address the professional needs of scholars.”
Confused about how to cite a source within a source? The site below from the University of Maryland University College provides an explanation and additional help on MLA 8th edition formatting.