Human equilibrative nucleoside transporter 1 and carcinoma of the ampulla of Vater: expression differences in tumour histotypes oleh G. Perrone, S. Morini, D. Santini, C. Rabitti, B. Vincenzi, R. Alloni, A. Antinori, P. Magistrelli, R. Lai, C. Cass, J. R. Mackey, R. Coppola, G. Tonini, A. Onetti Muda