article published in 2001

scientific article published on 20 April 2011

scholarly article by Susan Oosthuizen published in May 2016

scholarly article by Susan Oosthuizen published in December 2013

article

scientific article published on 2 January 2016

scientific article published in January 2013

scientific article published in January 1993

scientific article published in January 2009

scientific article

scientific article published in January 1997

scientific article published in January 2005

scientific article published in January 2014

scientific article published on 28 November 2015

scientific article published in September 1998

scientific article published in April 2003

scientific article published in January 2009

scientific article published in January 2010

book published in 2013

scientific article published in January 2000