"Among the features of this third edition of the thesaurus are: (1) Listing of new or not previously listed pharmaceuticals from the above countries. (2) Listing of new uses for previously identified pharmaceuticals. It should be noted that pharmaceutical usages as indicated in this thesaurus are those indicated in the literature of the countries involved, and do not necessarily coincide with US usage of the same compound. (3) Listing of country of origin of both new and previously identified pharmaceuticals whenever possible. The country of origin of the article in which the compound was mentioned is not presumed to be the country in which the compound is marketed under that name. Therefore, many compounds do not have a country of origin listed. (4) Listing of synonymous names for both new and previously identified pharmaceuticals. In accomplishing this objective two methods have been utilized. In some instances the literature specifically states that two compounds are synonymous. In addition, compounds synonymous to the same compound are considered synonymous to each other. Compounds with the same name but with different chemical formulas are listed as separate pharmaceuticals. (5) Identification of 'drugs of choice' in the USSR."