For copyright information, I suggest the copyright office at
http://www.copyright.gov/.
The proper use of copyright markings are defined there under copyright basics. An excerpt is here.
The notice for visually perceptible copies should contain all
the following three elements:
1 The symbol © (the letter C in a circle), or the word
“Copyright,” or the abbreviation “Copr.”; and
2 The year of first publication of the work. In the case of
compilations or derivative works incorporating previously
published material, the year date of first publication of
the compilation or derivative work is sufficient.
3 The name of the owner of copyright in the work, or an
abbreviation by which the name can be recognized, or a
generally known alternative designation of the owner.
Example: © 2008 John Doe