The coin-types of imperial Rome : by F. Gnecchi and G. Elmer. - Gnecchi, Francesco, 1847-1919 (Ares Publishers, 1978)
a partial translation of Gnecchi's handbook published in Numismatic Circular in 1908 and supplemented with an english translation of Elmer's the portrait coin-types of imperial Rome Added t. p: the portrait coin-types of imperial Rome: Emperors, Caesars, families, commemoratives & medals, by Georg Elmer.