Unveiling and tackling guanidinium peptide coupling reagent side reactions towards the development of peptide-drug conjugates - Vrettos, E.I.; Sayyad, N.; Mavrogiannaki, E.M.; Stylos, E.; Kostagianni, A.D.; Papas, S.; Mavromoustakos, T.; Theodorou, V.; Tzakos, A.G. (RSC Advances, 2017)