Document definition in information retrieval Is there common formal definition of Document in information retrieval field? In many researches authors don't define the term Document(maybe because it is evident for them). Wikipedia says "text file, document (computer science) a computer file that contains text" but it doesn't seem as common formal definition. 

Do you know the common formal definition of Document, or, if not, do you know any researches where that term was defined?
For a formal definition of document in the Information Retrieval context, you can look at IR glossaries.

A common definition is:


Document:  Specific unit of retrieval (usually text). It can be a web page, an article, a book, a section or chapter.


(see for example the Glossary of the book Modern Information Retrieval by 
Ricardo Baeza-Yates and Berthier Ribeiro-Neto)