Percival, W. Keith. 1964. A Grammar of Toba-Batak. New Haven: Yale University dissertation. (220pp.)
@phdthesis{gPercivalTobaBatak1964,
author = {Percival, W. Keith},
pages = {220},
school = {New Haven: Yale University},
title = {A Grammar of Toba-Batak},
year = {1964}
}