Long-term changes in the algal composition of the Vaal River, South Africa did the Lesotho Highlands Water Project play a role? - Janse van Vuuren, Sanet; Swanepoel, Annelie; van Zyl, Germarie (Suid-Afrikaans Tydskrif vir Natuurwetenskap en Tegnologie / South African Journal of Science and Technology, 2013)