Following is a bibliography on Babe Ruth. The list is small, but I included some books with small chapters and references to Ruth.
The Story of Babe Ruth: Baseball's Greatest Legend by Lisa Eisenberg (J BIO RUT)
Home Run Leaders by Jonathan Bliss (J 796.357 BLI) (Includes a chapter on Babe Ruth
The Babe & I by David A. Adler (E ADL)
Babe Ruth: Legend Comes to Life by Robert W. Creamer (BIO RUT)
Mighty Jackie: the Strikeout Queen by Marissa Moss (J Bio) The Story of Jackie Mitchell the first female professional baseball pitcher, who pitched against Babe Ruth and Lou Gerig in an exhibition game in 1931.
The Book of Time Outs by Deb Lucke (J 920 LUC) Tidbits about many great historical characters. Babe Ruth is included in this book.
Babe Ruth Biography.com http://www.biography.com/people/babe-ruth-9468009