Não informado. (2021). LC Classification, Additions and Changes. Library of Congress.
Chicago-viite (17. p.)Não informado. LC Classification, Additions and Changes. Washington: Library of Congress, 2021.
MLA-viite (8. p.)Não informado. LC Classification, Additions and Changes. Library of Congress, 2021.
Varoitus: Nämä viitteet eivät aina ole täysin luotettavia.