Cockrell, P J2012-07-132012-07-131991Cockrell, P.J. 1991. Geskiedenis en kognitiewe vaardigheidsverwerwing in die sekondêre skool. Yesterday & today = Gister en vandag, 22:17-22, Sep. [http://www.sashtw.org.za/index2.htm] [http://dspace.nwu.ac.za/handle/10394/5126]2223-0386http://hdl.handle.net/10394/6811otherArticle