Não informado. (2002). Canadian pit and quarry. National Business Publications.
Chicago-Zitierstil (17. Ausg.)Não informado. Canadian Pit and Quarry. Gardenvale, Canada: National Business Publications, 2002.
MLA-Zitierstil (8. Ausg.)Não informado. Canadian Pit and Quarry. National Business Publications, 2002.
Achtung: Diese Zitate sind unter Umständen nicht zu 100% korrekt.