Branko Grünbaum: What Symmetry Groups Are Present in the Alhambra? In: Notices of the American Mathematical Society. Bd. 53, Nr. 6, 2006, ISSN0002-9920, S. 670–673, Digitalisat (PDF; 1,97 MB).
Branko Grünbaum: The Emperor's New Clothes: Full Regalia, G string, or Nothing? In: The Mathematical Intelligencer. Bd. 6, Nr. 4, 1984, S. 47–53, doi:10.1007/BF03026738.
Doris Schattschneider: The Plane Symmetry Groups: Their Recognition and Notation. In: The American Mathematical Monthly. Bd. 85, Nr. 6, 1978, S. 439–450, doi:10.2307/2320063.
doi.org
Pólya, George (november 1924). "Über die Analogie der Kristallsymmetrie in der Ebene" [On the analog of crystal symmetry in the plane]. Zeitschrift für Kristallographie (tysk). 60 (1-6): 278-282. doi:10.1524/zkri.1924.60.1.278. S2CID102174323.
hathitrust.org
babel.hathitrust.org
E. Fedorov (1891) "Симметрія на плоскости" (Simmetrija na ploskosti, Symmetry in the plane), Записки Императорского С.-Петербургского минералогического общества (Zapiski Imperatorskogo Sant-Petersburgskogo Mineralogicheskogo Obshchestva, Proceedings of the Imperial St. Petersburg Mineralogical Society), series 2, 28 : 345–390 (in Russian).
Pólya, George (november 1924). "Über die Analogie der Kristallsymmetrie in der Ebene" [On the analog of crystal symmetry in the plane]. Zeitschrift für Kristallographie (tysk). 60 (1-6): 278-282. doi:10.1524/zkri.1924.60.1.278. S2CID102174323.
worldcat.org
Branko Grünbaum: What Symmetry Groups Are Present in the Alhambra? In: Notices of the American Mathematical Society. Bd. 53, Nr. 6, 2006, ISSN0002-9920, S. 670–673, Digitalisat (PDF; 1,97 MB).