Não informado. (1999). Shools in the middle. National Association of Secondary School Principals.
Citação do estilo Chicago (17ª ed.)Não informado. Shools in the Middle. Reston, Va: National Association of Secondary School Principals, 1999.
Citação MLA (8ª ed.)Não informado. Shools in the Middle. National Association of Secondary School Principals, 1999.
Предупреждение: эти цитированмия не могут быть всегда правильны на 100%.