To help you with any other questions you have about your infant and his/her development, here are a few recommended sources.
Caring For Your Baby and Young Child: Birth to Age 5 (The American Academy of Pediatrics manual) Steven Sherlov & Robert Haggeman
Your Child's Health by Barton Schmitt
The Baby Book by Dr. William Sears
Baby & Baby Care by Dr. Benjamin Spock & Michael R. Rothenberg
Your Baby and Child From Birth to Age 5 by Penelope Leach
The First Twelve Months of Life by Franklin Caplan, Grosset, & Dunlop Publishers
Infants and Mothers:Differences in Development by T. Berry Brazelton, M.D.
The Discipline Book by Dr. William Sears
The Womanly Art of Breastfeeding by La Leche League International