@article{Maree_Basson_Malan_2001, title={Optimising learning competencies of grade 9 learners: A comparison between a few subject didactic measuring instruments.}, volume={20}, url={http://satnt.ac.za/index.php/satnt/article/view/55}, DOI={10.4102/satnt.v20i3/4.255}, number={3/4}, journal={Suid-Afrikaans Tydskrif vir Natuurwetenskap en Tegnologie / <i>South African Journal of Science and Technology</i&gt;}, author={Maree, J. and Basson, N. and Malan, R.}, year={2001}, month={Sep.}, pages={80-93} }