?url_ver=Z39.88-2004&rft_id=MTMT%3A28012+10.1002%2Foms.1210280105&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.au=+Maki+Esa&rft.aulast=Maki&rft.aufirst=Esa&rft.volume=28&rft.issue=1&rft.date=1993&rft.title=ORGANIC+MASS+SPECTROMETRY&rft.issn=0030-493X&rft.pages=18-22&rft.atitle=Electron+impact+ionization+mass+spectra+of+some+substituted+dipyrido%5B1%2C2-a%3A4%2C3-d%5Dpyrimidinones&rft.genre=article