Operation Oaktree was a Dutch military operation in Dutch New Guinea during World War II. Under the command of Captain J.V. de Bruijn a group of around 40 men operated in enemy territory for more than two years between 1942 and 1944. It was handled by the Netherlands East Indies Forces Intelligence Service with Australian assistance.
- "NEFIS". Allies in Adversity: Australia and the Dutch in the Pacific War. Australian War Memorial. Retrieved 27 September 2015.
- ""No Indonesian Danger In N.G.", Says Visitor". The Sydney Morning Herald. National Library of Australia. 22 August 1950. p. 2. Retrieved 25 September 2015.