Handbook of number theory / by D.S. Mitrinović, J. Sándor ; in cooperation with B. CrsticiHandbook of number theory / József SándorHandbook of number theory / by József Sándor, Dragoslav Mitrinović and Borislav CrsticiHandbook of number theory / by József Sándor, Dragoslav Mitrinović and Borislav CrsticiHandbook of number theory / József SándorHandbook of number theory / József Sándor