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Bartmess, J.E.; Kester, J.; Borden, W.T.; Köser, H.G., Triphenylcyclopropenide Anion in the Gas Phase, Tetrahed. Lett., 1986, 27, 49, 5931, https://doi.org/10.1016/S0040-4039(00)85365-4 . [all data]