O'Kelly, M., Ryan-Enright, M., Whelan, D., & Cronin, M. (1989). Discover our world: Environmental studies; nature, civics, science (For fourth class.). Folens.
Citazione stile Chigago Style (17a edizione)O'Kelly, Mary, Mary Ryan-Enright, Deirdre Whelan, e Michael Cronin. Discover Our World: Environmental Studies; Nature, Civics, Science. For fourth class. Dublin: Folens, 1989.
Citatione MLA (9a ed.)O'Kelly, Mary, et al. Discover Our World: Environmental Studies; Nature, Civics, Science. For fourth class. Folens, 1989.
Attenzione: Queste citazioni potrebbero non essere precise al 100%.