Não informado. (2002). Principal Leadership. National Association of Secondary School Principals.
Chicago-Zitierstil (17. Ausg.)Não informado. Principal Leadership. Reston, Va: National Association of Secondary School Principals, 2002.
MLA-Zitierstil (8. Ausg.)Não informado. Principal Leadership. National Association of Secondary School Principals, 2002.
Achtung: Diese Zitate sind unter Umständen nicht zu 100% korrekt.