Web sites
Teens’ Friendship and Play (Education.com)
When You Don’t Like Your Kid’s Friends (WebMD)
Friendships (guide for teens for making positive friendships) (Medem)
Talking to Teens about Friendship (About.com)
Books:
You Be Me: Friendship in the Lives of Teen Girls, Anne Fleming, et al.
Queen Bees and Wannabes: Helping Your Daughter Survive Cliques, Gossip, Boyfriends, and Other Realities of Adolescence , Rosalind Wiseman
Good Friend: How to Make One, How to Be One (Boys Town Teens and Relationships), Ron Herron, Val J. Peter