Collis, M. (1974). Tackling problems part 1: A unit for teachers. Macdonald Educational.
Citazione stile Chigago Style (17a edizione)Collis, Margaret. Tackling Problems Part 1: A Unit for Teachers. London: Macdonald Educational, 1974.
Citatione MLA (9a ed.)Collis, Margaret. Tackling Problems Part 1: A Unit for Teachers. Macdonald Educational, 1974.
Attenzione: Queste citazioni potrebbero non essere precise al 100%.