Association of Natural Rubber Producing Countries & Barlow, C. (1976). The progress and development of rubber smallholders: Proceedings of the first seminar held in Medan, Indonesia, 25-27 February 1975. Association of Natural Rubber Producing Countries.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Association of Natural Rubber Producing Countries و Colin Barlow. The Progress and Development of Rubber Smallholders: Proceedings of the First Seminar Held in Medan, Indonesia, 25-27 February 1975. Kuala Lumpur: Association of Natural Rubber Producing Countries, 1976.
توثيق جمعية اللغة المعاصرة MLA (الطبعة الثامنة)Association of Natural Rubber Producing Countries و Colin Barlow. The Progress and Development of Rubber Smallholders: Proceedings of the First Seminar Held in Medan, Indonesia, 25-27 February 1975. Association of Natural Rubber Producing Countries, 1976.