Opus number developed other catalogue-number systems; among them the "Bach-Werke-Verzeichnis" (BWV-number), and the "Köchel-Verzeichnis" (K- and KV -numbers) with which are organised the works of Johann Sebastian Bach and Wolfgang Amadeus Mozart, respectively. In the classical period, the Latin word "opus" ("work", "labour") was used to identify, list, and catalogue a work of art. By the 15th and 16th centuries, the word "opus" was used by Italian composers to denote a specific musical composition, and by German composers for collections of music. In compositional practise, numbering musical works in chronological order dates from 17th century Italy, especially Venice. In common usage, the
Barefoot Catalogue Barefoot Catalogue The Barefoot catalogue is a series of catalogues of, mainly, revenue stamps published by stamp dealer John Barefoot of York, England, through his firm J. Barefoot Ltd. The catalogues are of an intermediate level of detail and while they are not usually the only revenue catalogue ever published for a given country, with highly specialised or historic local works sometimes existing, the low price, ready availability and up to date nature of the Barefoot range has meant that they have become the de facto standard revenue catalogue for many countries. In 2010, John Barefoot won the Research Medal