(2001). Vocational Education Directory, 1971 [United States] / United States Department of Education. National Center for Education Statistics. [electronic resource].
Citazione stile Chigago Style (17a edizione)Vocational Education Directory, 1971 [United States] / United States Department of Education. National Center for Education Statistics. [electronic Resource]. 2001.
Citatione MLA (9a ed.)Vocational Education Directory, 1971 [United States] / United States Department of Education. National Center for Education Statistics. [electronic Resource]. 2001.
Attenzione: Queste citazioni potrebbero non essere precise al 100%.