These are the books I use to carry out Number Psychology Training & Coaching to individuals and organization.

Refer : Energy Psychology and Number Psychologhy Service

The Number Psychology coaching framework is constantly improved with new ideas from books and actual application to hundreds over clients - and it is a on-going process. 

The Complete Book of Numerology - David Phillips	Numerology, The Complete Guide Matthew Goodwin The Life You Were Born to Live: A Guide to Finding Your Life Purpose - Dan Millman
Numerology- Hans Decoz
Numerology for the New Age - Lynn M. Buess	Life Cycles: Your Emotional Journey To Freedom And Happiness - Christine DeLorey
Enneagram Persoanlity System is now incorporated in my Number Psychology training. The following are the referrence books used.
The Tao of Chaos: Essence and the Enneagram by Stephen Wolinsky	Character Neurosis by Claudio Naranjo
The Enneagram by Helen Palmer	The Enneagram Made Easy by Baron and Wagele