For more information on infant sleep customs, go to the following link. This will lead you to an article from Zero To Three that explores "the complex developmental and relational issues surrounding infant sleep."
http://www.zerotothree.org/0-3_1198.html
For more information on crawling, go to the following web sites. The first will link to an article by Lois Barclay Murphy from Zero To Three entitled "Hopping, Jumping, Leaping, Skipping, and Loping: Savoring the Possibilities of Locomotion." The second will lead to an article by Murphy and Colleen Small from Zero To Three entitled "Parent Information: Toddlers: Themes and Variation." This article discusses young children as they develop locomotion.
http://www.zerotothree.org/hop.htmlhttp://www.zerotothree.org/toddler.html
