An expression is the specific intellectual or artistic form that a work takes each time it is "realized". Expression encompasses, for example, the specific words, sentences, paragraphs, etc. that result from the realization of a work in the form of a text, or the particular sounds, phrasing, etc. resulting from the realization of a musical work. The boundaries of the entity expression are defined, however, so as to exclude aspects of physical form, such as typeface and page layout, that are not integral to the intellectual or artistic realization of the work as such. Inasmuch as the form of expression is an inherent characteristic of the expression, any change in form (e.g., from alpha-numeric notation to spoken word) results in a new expression. Similarly, changes in the intellectual conventions or instruments that are employed to express a work (e.g., translation from one language to another) result in the production of a new expression. If a text is revised or modified, the resulting expression is considered to be a new expression. The degree to which bibliographic distinctions are made between variant expressions of a work will depend to some extent on the nature of the work itself, on the anticipated needs of users and on what the cataloguer can reasonably be expected to recognize from the manifestation being described. Differences in form of expression (e.g., the differences between the expression of a work in the form of musical notation and the expression of the same work in the form of recorded sound) will normally be reflected in the bibliographic record, no matter what the nature of the work itself may be. Variant expressions in the same form (e.g., revised versions of a text) will often be indirectly identified as different expressions because the variation is apparent from the data associated with an attribute used to identify the manifestation in which the expression is embodied (e.g., an edition statement). Variations that would be evident only from a more detailed analysis and comparison of expressions (e.g., variations between several of the early texts of Shakespeare's Hamlet) would normally be reflected in the data only if the nature or stature of the work warranted such analysis, and only if it was anticipated that the distinction would be important to users.