For further research:

AAP Info For Parents:
FAQ on Breastfeeding
Common Concerns While Breastfeeding

Professional Best Practice Guidelines:
AAP Policy Statement on Breastfeeding
Best Practices Guidelines
of the Royal Women's Hospital, Melbourne AU

Also helpful:
How Does Milk Production Work?
by Kelly Bonyata, BS, IBCLC

The following links contain charts & analyses which compare and contrast the Ezzos' advice in Babywise with that of the AAP. Ezzo has claimed his advice is in harmony with that of the AAP, and illustrates the point in Babywise by quoting from an AAP publication.

Analysis of GFI's Babywise/AAP Comparison Chart
A pediatrician evaluates a comparison chart that GFI created.

Breastfeeding Frequency: The AAP vs. Babywise & Baby Whisperer
comparison chart by Dr. Anh Gordon, et al