1
by Llamzon, T.A.
Published 1969
Brill

2
by Malchukov, Andrej
Published 2017
Language Science Press

3
by Townsend, Grant C
Published 2015
University of Adelaide Press

4
by van der Stap, P.
Published 1966
Brill

5
by Koizumi, Masatoshi
Published 2023
De Gruyter