(Male (Low and High Voice)). By Jeffrey Allen. For Voice (High voice (Medium-High); Low voice (Medium-Low); Male voice). Method/Instruction; Vocal Method. Book and 2 CDs. 392 pages. Published by Alfred Music Publishing

(Female (Low and High Voice)). By Jeffrey Allen. For Voice (Female voice; High voice (Medium-High); Low voice (Medium-Low)). Method/Instruction; Vocal Method. Book and 2 CDs. 392 pages. Published by Alfred Music Publishing

Performing, Auditioning, and Rehearsing. By Carolyn Wilkins. Berklee Guide. Softcover with CD. 110 pages. Published by Berklee Press.

A Practical Guide to the Benefits of Singing. Composed by Stacey DeLooze. Method/Instruction; Textbook - Choral / Vocal; Vocal Resources. Faber Edition. Book. 160 pages. Faber Music #12-0571541763. Published by Faber Music