CBD oils on the Belgian market: A validated MRM GC-MS/MS method for routine quality control using QuEChERS sample clean up, Duchateau, Céline, Canfyn Michael, Desmedt Bart, Kauffmann Jean-Michel, Stévigny Caroline, De Braekeleer Kris, and Deconinck Eric , Journal of Pharmaceutical and Biomedical Analysis, Jan-10-2021, Volume 205, (2021)