Christian Copyright Licensing International – For music lyric permissions
Publishing Law Forum – I highly recommend this site. (Read this page first!)
Copyright Clearance Center – Register your for work for use by others or to obtain permission
How to Cite Material Obtained from the Internet – Chicago Manual of Style (This is the style guide all book publishers use.)
Buy the book, The Copyright Handbook: How to Protect and Use Written Works 12th Edition by Stephen Fishman, Nolo Press (2014).
Buy the book, The Copyright Permission and Libel Handbook : A Step-By-Step Guide for Writers, Editors, and Publishers(Wiley Books for Writers) by by Lloyd J. Jassin and Steve C. Schecter, John Wiley & Sons Publishing. – Published in 1998 but still a fine resource.