Hachette This This is a Voice: 99 exercises to train, project and harness the power of your voice Paperback – Big Book, 23 August 2018

This is a Voice: 99 exercises to train, project and harness the power of your voice

Anatomy Of The Voice: An Illustrated Guide for Singers, Vocal Coaches, and Speech Therapists

Korg - VPT-1 Vocal Pitch Trainer