Bergholm, J. (2001). Long-term effects of enhanced nitrogen and sulphate additions on soil acidification and nutrient cycling in a Norway spruce stand. Swedish University of Agricultural Sciences.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Bergholm, Johan. Long-term Effects of Enhanced Nitrogen and Sulphate Additions on Soil Acidification and Nutrient Cycling in a Norway Spruce Stand. Uppsala: Swedish University of Agricultural Sciences, 2001.
توثيق جمعية اللغة المعاصرة MLA (الطبعة الثامنة)Bergholm, Johan. Long-term Effects of Enhanced Nitrogen and Sulphate Additions on Soil Acidification and Nutrient Cycling in a Norway Spruce Stand. Swedish University of Agricultural Sciences, 2001.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.