REFERENCE MATERIALS
· B > LIBRARY MATERIALS
· N > ATLASES
· N > BIBLIOGRAPHY
· N > BIOGRAPHY
· N > CATALOGS
· N > DIRECTORIES
· N > ENCYCLOPAEDIAS AND DICTIONARIES
· N > GLOSSARIES, VOCABULARIES ETC.
· N > HANDBOOKS, MANUALS ETC.
· N > THESAURI
· R > EDUCATIONAL AIDS