How did the philosopher Jean-Paul Sartre contribute to Epistemology? What did he say about knowledge and truth?

Does anyone know the answer? If you have a source with these information, please paste it. Thanks|||Imo, next to nothing (pun intended).





A more intellectual appraisal: http://www.iep.utm.edu/sartre-ex





Semi-source: "Nihilism," Eugene Rose. Review at http://www.amazon.com