Não informado. (1980). Principal. National Association of Elementary School Principals.
Chicago-viite (17. p.)Não informado. Principal. Arlington, Va: National Association of Elementary School Principals, 1980.
MLA-viite (8. p.)Não informado. Principal. National Association of Elementary School Principals, 1980.
Varoitus: Nämä viitteet eivät aina ole täysin luotettavia.