International Federation of Organic Agriculture Movements (IFOAM). IFOAM Internal Letter. Tholey-Theley: IFOAM.
芝加哥风格引文International Federation of Organic Agriculture Movements (IFOAM). IFOAM Internal Letter. Tholey-Theley: IFOAM.
MLA引文International Federation of Organic Agriculture Movements (IFOAM). IFOAM Internal Letter. Tholey-Theley: IFOAM.
警告：这些引文格式不一定是100％准确.