Svenonius, B. (1938). Contributions to the photographic study of colour, resolution and total magnitude of anagalactic objects: With special regard to objects photographed at Helwan, by. Published by the Observatory.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Svenonius, Björn. Contributions to the Photographic Study of Colour, Resolution and Total Magnitude of Anagalactic Objects: With Special Regard to Objects Photographed at Helwan, by. Lund, Sweden: Published by the Observatory, 1938.
توثيق جمعية اللغة المعاصرة MLA (الطبعة الثامنة)Svenonius, Björn. Contributions to the Photographic Study of Colour, Resolution and Total Magnitude of Anagalactic Objects: With Special Regard to Objects Photographed at Helwan, by. Published by the Observatory, 1938.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.