Below is a list of many music-related links. The first site is the recommended site for purchasing required and recommended books. Jendza Music Studio gets 4% of your purchase back for studio purchases to enhance your learning experience.
Jendza Music Studio Amazon Associates
http://www.bulletproofmusician.com/how-many-hours-a-day-should-you-practice/
American Choral Directors Association
National Association for Music Education
Music Teachers National Association
National Association of Teachers of Singing