"One of the easiest and most useful ways to search the historical databases created by the Bioethics Research Library at Georgetown University is to browse its classification scheme.
Developed by the National Reference Center for Bioethics Literature to encompass the wide diversity found in the cross-disciplinary area of bioethics, it is used as a subject index to the extensive collection of periodical literature. Numbered from 1 to 22, beginning with general ethics, bioethics and philosophy of science, it becomes more specific as the numbers rise. Subdivisions within each main category point out specific topics within particular areas. The largest categories are 9 – Health Care, 18 – Human Experimentation, and 20 – Death and Dying."