Não informado. (2002). Principal Leadership. National Association of Secondary School Principals.
Chicago (17e ed.) BronvermeldingNão informado. Principal Leadership. Reston, Va: National Association of Secondary School Principals, 2002.
MLA (8e ed.) BronvermeldingNão informado. Principal Leadership. National Association of Secondary School Principals, 2002.
Let op: Deze citaties zijn niet altijd 100% accuraat.