International Federation of Organic Agriculture Movements (IFOAM). IFOAM Internal Letter. Tholey-Theley: IFOAM.
Cita Chicago (17th ed.)International Federation of Organic Agriculture Movements (IFOAM). IFOAM Internal Letter. Tholey-Theley: IFOAM.
Cita MLA (8th ed.)International Federation of Organic Agriculture Movements (IFOAM). IFOAM Internal Letter. Tholey-Theley: IFOAM.
Atenció: Aquestes cites poden no estar 100% correctes.