the Elder, P., & Healy, J. F. (1991). Natural history: Selection. Penguin Books.
Citazione stile Chigago Style (17a edizione)the Elder, Pliny, e John F. Healy. Natural History: Selection. London: Penguin Books, 1991.
Citatione MLA (9a ed.)the Elder, Pliny, e John F. Healy. Natural History: Selection. Penguin Books, 1991.
Attenzione: Queste citazioni potrebbero non essere precise al 100%.