@book{
title = {Heidi},
author = {Turvey, Celia},
editor = {Julian-Ottie, Vanessa},
editor = {Spyri, Johanna},
editor = {Versione abbreviata e semplificata ad uso scolastico },
editor = {Con apparato didattico },
year = {1991},
address = {Harlow },
publisher = {Longman},
}