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
K. S. Chithra arrangement since 2001. Apart from music cds the audiotracs catalogue is available in the digital space like YouTube, iTunes, Google+, Nokia music store etc. Krishna Digidesign is a digital recording studio promoted by K S Chithra in Chennai. The studio is a dream come true project for Chithra.The studio was inaugurated on 6 April 2000 jointly by two of Chithra's mentors K J Yesudas and mastero Ilayaraja in the august presence of her guru Omanakutty and M. G. Radhakrishnan who had introduced her to the field of film music. The first song was recorded by Sonu Nigam to the music