Khazaie, Y.; Dorkoosh, F. A.; Novo, L.; Gaal, E. van; Fassihi, A.; Mirahmadi-Zareh, S. Z.; Esfahani, M. H. N.; van Nostrum, C. F.; Hennink, W. E. Poly[N-(2-aminoethyl)ethyleneimine] As a New Non-Viral Gene Delivery Carrier: The Effect of Two Protonatable Nitrogens in the Monomer Unit on Gene Delivery Efficiency. J Pharm Pharm Sci 2014, 17, 461-474.