@article{Kruger_du Preez_2012, title={Frogs change their tune}, volume={31}, url={http://www.satnt.ac.za/index.php/satnt/article/view/308}, DOI={10.4102/satnt.v31i1.319}, number={1}, journal={Suid-Afrikaans Tydskrif vir Natuurwetenskap en Tegnologie / <i>South African Journal of Science and Technology</i&gt;}, author={Kruger, Donnavan and du Preez, Louis}, year={2012}, month={May}, pages={1 bladsy} }