  We have counted the number of references in 1179 papers published in
Astronomy and Astrophysics over twenty years. The number of references has
increased by 60% between 1975 and 1995, reflecting the increase (by the same
amount) of the literature which must be cited, and of the number of pages per
paper. There are 1.5 times more references in predominantly observational
fields than in others. References are used 1.65 times in the text, and there is
no trend with time or field. They appear mostly in the introduction (30%) and
in the main body of the paper (60%), but papers in predominantly observational
fields tend to use less references in the introduction and more in the main
body than papers in the other fields. Most references (62%) serve to support a
result, and tend to be of theoretical nature. Astronomers are a very conformist
bunch, as there are no trends with nationality, and references to conflicting
evidence are kept at about 8%. The analysis of a series of papers by de
Vaucouleurs on the Hubble constant shows how a controversial subject affects
the use of references.
