in 1895, the german scholar hans dragendorff produced a classification of vessel shapes in roman red gloss pottery that is still used (as e.g. "drag. 27" or "dr.27" to refer to the small biconvex-profiled cup). other scholars added to his numbered forms, and some archaeologists working on the products of specific manufacturing sites, or the finds from important excavations, initiated their own typologies, so that there are now many other classification systems for arretine and samian, as there are, indeed, for other classes of roman pottery, such as the hayes numbers for african red slip forms. other numbering systems used with italian and gaulish sigillata include those of déchelette, knorr, curle, walters, loeschcke, ritterling and ludowici, to name but a few.