I found a list of books on Madhubani paintings or books having references to this art form from http://www.vl-site.org/india/mithila/books.html

Here goes the list--

Anand, Mulk Raj, Madhubani Painting (New Delhi: Publications Division, Ministry of Information and Broadcasting, Government of India, 1984).

Archer, Mildred, Indian Popular Painting in the India Office Library (London: Her Majesty's Stationery Office, 1977).

Archer, William G., Songs for the Bride: Wedding Rites of Rural India, ed. by Barbara Stoler Miller and Mildred Archer (New York: Columbia University Press, 1985).

Brown, Carolyn Henning, "Contested Meanings: Tantra and the Poetics of Mithila Art," American Ethnologist 23, 4 (November 1996), 717-37.
[All of the listed titles can be read more profitably in relation to the proposals put forward by Professor Brown.]

Brown, Carolyn Henning, "The Women Painters of Mithila," in Festival of India in the United States 1985-1986 (New York: Harry N. Abrams, Inc., 1985), 155-61.

Craven, Roy C., A Concise History of Indian Art (London: Thames and Hudson; New York: Praeger, 1976).

Craven, Roy C., Indian Art: A Concise History, revised edition (London: Thames and Hudson, 1997).

Jayakar, Pupul, The Earth Mother: Legends, Ritual Arts, and Goddesses of India (San Francisco: Harper & Row, Publishers, 1990).

Jain, Jyotindra, Ganga Devi: Tradition and Expression in Mithila Painting (Ahmedabad, India: Mapin Publishing Pvt Ltd., in association with The Mithila Museum, Niigata, Japan, 1997).
[A fine book on a leading artist who practiced what is sometimes called the Kayastha style of Madhubani painting.]

Mode, Heinz and Subodh Chandra, Indian Folk Art (New York: Alpine Fine Arts Collection, Ltd., 1985).
[Useful for background and comparative study.]

Thakur, Upendra, Madhubani Painting (New Delhi: Abhinav Publications, n.d.).

Vequaud, Yves, The Women Painters of Mithila (London: Thames and Hudson, 1977).
[This is a book that contributed to and then reflected the worldwide popularity of Madhubani painting.]