Hutchins, W. J. (1975). ''Languages of indexing and classification. A linguistic study of structures and functions''. London: Peter Peregrinus. 
 
Hutchins, W. J. (1977). On the Problem of "Aboutness" in Document Analysis. ''Journal of Informatics, 1'', 17-35.
 
Hutchings, W. J. (1978). The concept of "aboutness" in subject indexing. ''Aslib Proceedings'', 30, 172-181.
 
Mark Peitersen, A. (1979). The meaning of "about" in fiction indexing and retrieval. ''Aslib Proceedings'', 31, 251- 257.
 
Maron, M. E. (1977). On Indexing, Retrieval and the Meaning of About. ''Journal of the American Society for Information Science'', 28, 38-43.
Filosofi Biblioteks-_og_informationsvidenskab