Broadhurst, J. H. (1959). The development and use of a physical method for measuring the penetration of oxygen into coals. University of Birminghaml.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Broadhurst, John Henry. The Development and Use of a Physical Method for Measuring the Penetration of Oxygen into Coals. England: University of Birminghaml, 1959.
توثيق جمعية اللغة المعاصرة MLA (الطبعة الثامنة)Broadhurst, John Henry. The Development and Use of a Physical Method for Measuring the Penetration of Oxygen into Coals. University of Birminghaml, 1959.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.