The following books cover kyerim/generation stage practice:
The Kalachakra Tantra by HH Dalai Lama (on Kalachakra tantra)
Union of Indivisible Method and Wisdom by Geshe Thubten Loden (specifically on the Yamantaka system)
Swift Path to Kechara Paradise by Geshe Tharcin (generation stage of Vajrayogini)
There are more general books that include instructions on the philosophy, psychology and spiritual technology behind generation stage practices that I highly recommend for practitioners of all deities:
Principles of Buddhist Tantra from the late Kirti Tsenzhab Rinpochehttp://www.wisdom-books.com/ProductDetail.asp?PID=22281
To understand the method of Bringing the Three Bodies into the path which is the crux of generation stage practice this book is indispensible:
Death, Intermediate State and Rebirth in Tibetan Buddhism by Lati Rinpoche and Jeffrey Hopkinshttp://www.wisdom-books.com/ProductDetail.asp?PID=22281
In order to ensure my mind never comes under the power of the self-cherishing attitude,
I must obtain control over my own mind.
Therefore, amongst all empowerments, the empowerment that gives me control over my mind is the best,
and I have received the most profound empowerment with this teaching.
brtsal ba'i bkhra drin