Petreska Stanoeva, J.; Stefova, E.; Cvetanoska, M.; Bogdanov, J. Establishing Mass Spectral Fragmentation Patterns for Characterization of 1,2 -Unsaturated Pyrrolizidine Alkaloids and N-Oxides in Boraginaceae Species from Macedonia Using LC-ESI-MS/MS. Maced. J. Chem. Chem. Eng. 2022, 41.