Não informado. Soil and land-use surveys. University of the West Indies, Department of Soil Science.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Não informado. Soil and Land-use Surveys. St. Augustine, Trinidad e Tobago: University of the West Indies, Department of Soil Science.
توثيق جمعية اللغة المعاصرة MLA (الطبعة الثامنة)Não informado. Soil and Land-use Surveys. University of the West Indies, Department of Soil Science.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.