1
by van Stipriaan, A.
Published 1993
Brill

2
by Hofmann, Simon
Published 2016
transcript Verlag

3
by van Stipriaan, Alex
Published 1993
Brill

4
by Lephoko, Dan S.B.
Published 2018
AOSIS

5
by Botting, Jack
Published 2015
Open Book Publishers