• This study results from the knowledge of the insufficiency in standards and rules used for the identification and description of written musical documents. Enlightened by the new standard development, particularly the Functional Requirements for Bibliographic Records (FRBR) and recent studies on the concept of a work and bibliographic relationships, it must achieve an equilibrium between the music cataloguing rules normally used on libraries, much generalist, and the rules usually used by musicologists for the description of the same documents, particularly RISM rules, much specific an inaccessible to a less specialized public. Some proposals are made in order to contribute to the current revision of FRBR, ISBD(PM) and UNIMARC format for music. The final result is expectable to be a description model according to the practice and the spirit to the library cataloguing, but detailed enough to result in a useful tool to musicians and musicologists. The model was tested in a sample of bibliographic records from the opera Lauriane, composed by Augusto Machado.