by Bogat, G A, Caldwell, R A, Rogosch, F A, Kriegler, J A
Published in Journal of youth and adolescence (01.02.1985)

by van Zyl, J., Kriegler, A., Koch, H. and van der Walt, B
Published in South African journal of science (01.10.1988)

by van Zyl, J., Kriegler, A., Koch, H. and van der Walt, B.
Published in South African journal of science (01.10.1988)