Sheldon, C., & Yoxon, M. (2007). Environmental management systems: A step-by-step guide to implementation and maintenance (3rd ed.). Earthscan.
Chicago-viite (17. p.)Sheldon, Christopher, ja Mark Yoxon. Environmental Management Systems: A Step-by-step Guide to Implementation and Maintenance. 3rd ed. London ; Sterling, VA: Earthscan, 2007.
MLA-viite (8. p.)Sheldon, Christopher, ja Mark Yoxon. Environmental Management Systems: A Step-by-step Guide to Implementation and Maintenance. 3rd ed. Earthscan, 2007.
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