I have listed a partial bibliography of useful books on subjects related to Girls Underground, as well as some websites on relevant folklore and mythology. 

SUGGESTED READING:

Valente, Catherynne M. "Follow the Yellow Brick Road: Katabasis and the Female Hero in Alice in Wonderland, The Wizard of Oz, and The Nutcracker Ballet," presented at Wiscon, Feminism in SF/F Convention, 2005.
[This is the closest discussion of what could be seen as the Girls Underground archetype that I have ever seen outside my own work. A fascinating essay comparing these three popular stories to the myths of Persephone and Inanna.  Can be found on her website.]

Estes, Clarissa Pinkola. Women Who Run With the Wolves. Ballantine Books, 1996.
Grimm, Jacob, et al. The Annotated Brothers Grimm. WW Norton & Co, 2004.
Ragan, Kathleen. Fearless Girls, Wise Women, and Beloved Sisters: Heroines in Folktales from Around the World. WW Norton & Co, 2000.
Tatar, Maria. Secrets Beyond the Door : The Story of Bluebeard and His Wives. Princeton University Press, 2004.
Tatar, Maria. The Hard Facts of the Grimms' Fairy Tales. Princeton University Press, 2003.
Zipes, Jack. The Trials and Tribulations of Little Red Riding Hood. Routledge, 1993.

WEBSITES:

Folklore and Mythology Electronic Texts - tales by type
Sur La Lune Fairy Tales - the ultimate resource for many popular fairytales
Cabinet des Fees - an online fairytale journal
Journeying and Fairytales - an intersection with shamanism