International Federation of Organic Agriculture Movements (IFOAM). IFOAM Internal Letter. Tholey-Theley: IFOAM.
Chicago-referens (17:e uppl.)International Federation of Organic Agriculture Movements (IFOAM). IFOAM Internal Letter. Tholey-Theley: IFOAM.
MLA-referens (8:e uppl.)International Federation of Organic Agriculture Movements (IFOAM). IFOAM Internal Letter. Tholey-Theley: IFOAM.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.