1. Beilstein Online Database ; Heller, S., Ed.; ACS Symposium Series 436; American Chemical Society: Washington, 1990.
2. Jochum, C. ‘Building a Structure-Oriented Numerical Factual Database’. In Chemical Structures: The International Language of Chemistry; Warr, W.A., Ed.; Springer- Verlag: Berlin, 1988, pp. 187–193.
3. Details of individual programs may be obtained from the Computing Division, Beilstein Institute, Varrentrappstr. 40-42, W-6000 Frankfurt, Germany.
4. Dittmar, P.G.; Stobaugh, R.E.; Watson, C.E. ‘The Chemical Abstracts Registry System. I. General Design’. J. Chem. Inf. Comput. Sci. 1976, 16, 111–121, and subsequent papers.
5. Barnard, J.M.; Jochum, C.; Welford, S.M. In Chemical Structure Information Systems; Warr, W.A., Ed.; ACS Symposium Series No. 400; American Chemical Society: Washington, 1989, pp. 76–81.