Lorrain, Reginald Arthur. 1951. "Grammar and Dictionary of the Lakher or Mara Language." Department of Historical and Antiquarian Studies, Government of Assam.
D. C. Laycock and John A. Z'graggen. 1975. "The Sepik-Ramu Phylum." In Papuan Languages and the New Guinea Linguistic Scene, New Guinea Area Languages and Language Study 1, edited by S.A. Wurm. 38: 729-763. Australian National University.
Last, Marco and Deborah Lucassen. 1998. "A Grammatical Sketch of Chai, a Southeastern Surmic Language." In Surmic Languages and Cultures, edited by Gerrit J. Dimmendaal and Marco Last. 375-436. Rüdiger Köppe.
Oswin Köhler. 1981. "La Langue Kxoe." In Les langues dans le monde ancien et moderne, edited by Jean Perrot. 483-555. Centre National de la Recherche Scientifique.