Fowler, A. (2000). The virtuous spiral: A guide to sustainability for non-governmental organisations in international development. Earthscan.
Chicago-referens (17:e uppl.)Fowler, Alan. The Virtuous Spiral: A Guide to Sustainability for Non-governmental Organisations in International Development. London ; Sterling, VA: Earthscan, 2000.
MLA-referens (8:e uppl.)Fowler, Alan. The Virtuous Spiral: A Guide to Sustainability for Non-governmental Organisations in International Development. Earthscan, 2000.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.