1. American National Standards Institute (1984). American national standard for library and information sciences and related publishing practices?basic criteria for indexes (ANSI Z39. 4-1984)/Secretariat, Council of National Library and Information Associations; approved December 2, 1983, American National Standards Institute, Inc. New York, NY: ANSI, 1984.
2. (1997). Guidelines for Indexes and Related Information Retrieval Devices (NISO Technical Report 2, NISO-TR02- 1997). Bethesda, MD: NISO Press.
3. As we may think