15Van der Berg, Servaas, Cobus Burger, Ronelle Burger, Mia Vos, Gideon Rand, Martin Gustafsson, Eldridge Moses, Debra Shepherd, Nicholas Spaull, and Stephen Taylor. "Low quality education as a poverty trap." (2011).
16Puukka, Jaana, Patrick Dubarle, Holly McKiernan, Jairam Reddy, and Philip Wade. The Free State, South Africa.: OECD, 2012.