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.
Chicago-referens (17:e uppl.)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.
MLA-referens (8:e uppl.)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.
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