Scott, Mona L. Dewey decimal classification, 21st edition : a study manual and number building guide / Mona L. Scott. - Englewood, Colo. : Libraries Unlimited, 1998. - ix, 198 p. ; 25 cm. Includes index. Includes bibliographical references: p. 183-186. ISBN: 1563085984 (cased) Subjects--Topical Terms: Classification, Dewey decimal.