Holmberg, E. (1937). A study of double and multiple galaxies, together with inquiries into some general metagalactic problems: With an appendix containing a catalogue of 827 double and multiple galaxies. Published by the Observatory.
توثيق أسلوب شيكاغو (الطبعة السابعة عشر)Holmberg, Erik. A Study of Double and Multiple Galaxies, Together with Inquiries into Some General Metagalactic Problems: With an Appendix Containing a Catalogue of 827 Double and Multiple Galaxies. Lund, Sweden: Published by the Observatory, 1937.
توثيق جمعية اللغة المعاصرة MLA (الطبعة الثامنة)Holmberg, Erik. A Study of Double and Multiple Galaxies, Together with Inquiries into Some General Metagalactic Problems: With an Appendix Containing a Catalogue of 827 Double and Multiple Galaxies. Published by the Observatory, 1937.
تحذير: قد لا تكون هذه الاستشهادات دائما دقيقة بنسبة 100%.