The Library of Congress and the American Library Association transcription scheme for Tibetan can be found documented on the corresponding ALA-LC romanization page. This scheme is important for its use in library catalogs. However, it is never used by scholars or others in contemporary publications. It is similar to Wylie, but a number of characters represented by two letters in Wylie are instead represented by a single letter plus special diacritic mark in the ALA-LC scheme.