National District Heating Association. Official proceedings, Annual meeting of the National District Heating Association. National District Heating Association.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)National District Heating Association. Official Proceedings, Annual Meeting of the National District Heating Association. Pittsburgh, Pa.: National District Heating Association.
توثيق جمعية اللغة المعاصرة MLA (الطبعة الثامنة)National District Heating Association. Official Proceedings, Annual Meeting of the National District Heating Association. National District Heating Association.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.