Some references to support this definition of modes:
http://www.engr.mun.ca/~whitt/bass/modes.html
http://www.reference.com/browse/wiki/Musical_mode
http://en.wikipedia.org/wiki/Musical_mode
http://www.8notes.com/articles/modes/
http://www.answers.com/topic/properties-of-musical-modes
http://trillian.mit.edu/~jc/music/abc/doc/Modes.html
