Giorgi, J. (2009). Math for wastewater treatment operators grades 1 and 2: A guide to preparing for wastewater treatment operator certification exams. American Water Works Association.
Trích dẫn kiểu Chicago (xuất bản lần thứ 7)Giorgi, John. Math for Wastewater Treatment Operators Grades 1 and 2: A Guide to Preparing for Wastewater Treatment Operator Certification Exams. Denver, Colo.: American Water Works Association, 2009.
Trích dẫn kiểu MLA (xuất bản lần thứ 9)Giorgi, John. Math for Wastewater Treatment Operators Grades 1 and 2: A Guide to Preparing for Wastewater Treatment Operator Certification Exams. American Water Works Association, 2009.
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