Zagzebski's 1994 article, published in the journal The Philosophical Quarterly, is a famous contribution to the literature on Gettier Problems. Rather than suggesting yet another (doomed) solution, Zagzebski argues that any analysis of knowledge that fits certain plausible conditions will be plagued by Gettier problems; she even gives a sort of recipe for constructing them.
Victor Gijsbers teaches philosophy at Leiden University in the Netherlands. This video is part of an ongoing look at various philosophical papers: https://www.youtube.com/playlist?list=PL8Nxd4OXpzqldzrAdT2O5Xv4aJrtEV-b8