The Chicago Manual of Style (CMS) is the source most often used for Music Department assignments and papers. Be sure to check if your instructor requires CMS 16th or 17th edition. Here are some links to help you:
The Chicago Manual of Style (Print & Online) by 
The Chicago Manual of Style - 17th ed, by 
A Manual for Writers of Research Papers, Theses, and Dissertations, Eighth Edition by 