Dutch photographer Peter Martens (1937-1992) was a versatile street photographer. His way of working was inspired by the long American tradition of engaged and personal documentary photography, but he went one step further and developed into a radical photographer who took a stand for the disadvantaged and outcast.
Source
http://www.post-editions.com/?page=petermartens
Magnum Foundation Archive, MF014-001, Box 1, Membership Chronology