D. C. Laycock. 1975. "Sko, Kwomtari and Left May (Arai) Phyla." In New Guinea Area Languages and Language Study Vol 1: Papuan Languages and the New Guinea linguistic scene, edited by Stephen A. Wurm. 38: 849-858. Canberra: Research School of Pacific and Asian Studies, Australian National University.
D. C. Laycock. 1973. "Sepik Languages: Checklist and Preliminary Classification." 25: Canberra: Research School of Pacific and Asian Studies, Australian National University.
D. C. Laycock. 1975. "Isolates: Sepik Region." In New Guinea Area Languages and Language Study Vol 1: Papuan Languages and the New Guinea linguistic scene, edited by Stephen A. Wurm. 38: 879-886. Canberra: Research School of Pacific and Asian Studies, Australian National University.
Larish, Michael David. The Position of Moken and Moklen Within the Austronesian Language Family (Thailand). PhD thesis, University of Hawai'I at Manoa, 1999.