Philips, J. (2018). PMP Project Management Professional: Study Guide (fifth.). Mc Graw Hill.
Chicago (17e ed.) BronvermeldingPhilips, John. PMP Project Management Professional: Study Guide. fifth. New York: Mc Graw Hill, 2018.
MLA (9e ed.) BronvermeldingPhilips, John. PMP Project Management Professional: Study Guide. fifth. Mc Graw Hill, 2018.