"Operation Bittern (Norwegian: Bittern-ekspedisjonen, known as Bitern in the oldest sources) was a military operation in occupied Norway planned and carried out in 1942 by the British Special Operations Executive (SOE) and the Norwegian government-in-exile in London. Four SOE agents and instructors\u2014Thor Helliessen, Jan Allan, Ruben Langmo and Johannes S. Andersen\u2014were sent to Norway and parachuted into Nordmarka north of Oslo in October 1942."@en .