  In the secondary literature, references to texts of Herculaneum papyri are usually given in terms of the inventory number, then column or fragment number, then line number (e.g., PHerc. 1497.21.14; often, columns have Roman numerals). Older publications will refer to the volume and page number of the engraved facsimile, e.g., V(olumina) H(erculanensia)2 XII 67. Many publications give volume and page numbers of a standard late-19th or early 20th century edition, as for Sudhaus 1892–6 and Jensen 1907 and 1911.