Wilhelms, F. T. (1973). Supervision in a new key. Association for Supervision and Curriculum Development.
Citazione stile Chigago Style (17a edizione)Wilhelms, Fred T. Supervision in a New Key. Washington: Association for Supervision and Curriculum Development, 1973.
Citatione MLA (9a ed.)Wilhelms, Fred T. Supervision in a New Key. Association for Supervision and Curriculum Development, 1973.
Attenzione: Queste citazioni potrebbero non essere precise al 100%.