A scientific paper usually contains a bibliography of earlier literature that has been consulted by the author during the course of his work, and the following up of such references has always been a fruitful and well‐used method of tracing earlier information on a subject. Some figures given in a recent Aslib research report confirm this. Of the twelve methods which a group of scientists used to seek information, the following up of references cited in relevant papers was the most popular method, practised by 80 per cent of the sample.