5. THE EVENTS MICRO-THESAURI With a three-level list, three groups of digits are used. Shown below is the first part of Microthesaurus 12: Religions: 01 01 01 01 02 02 03 04 05 06 07 08 09 10 10 01 10 02 10 03 10 04 10 04 01 10 04 02 10 04 03 10 04 04 10 05 10 99 Buddhists Lamaists Zen Buddhists Jains Confucianists Hindus Sikhs Bahais Shintoists Taoists Zoroastrians Christians Orthodox Christians Copts Catholics Protestants Huguenots Lutherans Baptists Pentecostals Jehovah‟s Witnesses Other Christian groups A four-level list uses four groups of digits while a five-level list uses five groups. All six groups of digits are used for six-level lists. 5.5 EXPANDING THE HIERARCHICAL LISTS Users who want to make any of the hierarchical lists more specific can do so by adding a new group of digits to the right of currently used groups. For instance, a user may want to add more specific terms to Micro-thesaurus 15: Geographical Terms as follows: 01 01 01 01 01 17 01 01 17 01 01 01 17 02 48 Africa Central Africa Burundi Northern Burundi Central Burundi