^Karolanos at Ethnologue (18th ed., 2015) (subscription required)
^Gonzaga, V. L. (1988). The roots of agrarian unrest on Negros, 1850–90. Philippine Studies, 36(2), 151–165.
^Lobel, Jason William (2013). Philippine and North Bornean Languages: Issues in Description, Subgrouping, and Reconstruction (PDF) (Ph.D. dissertation). University of Hawai'i at Manoa.