The Elements of Style by William Strunk, Jr.
This book illustrates the principal requirements of plain English style and concentrates attention on the rules of usage and principles of composition most commonly violated.
MLA 7 Made Easy
This work presents 10 chapters organized into three parts: Understanding and Creating MLA Citations, Parenthetical Documentation, and Formatting.
OWL (Online Writing Lab) @ Purdue
The Online Writing Lab (OWL) at Purdue University is a well established writing resource for guidance in grammar, citation formatting, research strategies, ESL resources, subject-specific writing, and more.
The Writer’s Handbook
From the Writing Center of the University of Wisconsin. This resource demonstrates several citation styles and tips for improving your writing.