Hilton, Peter; Pedersen, Jean, Symmetry in mathematics, Computers & Mathematics with Applications, 1986, 12 (1-2): 315–328, MR 0838152, doi:10.1016/0898-1221(86)90157-4
Janner, Aloysio, DNA enclosing forms from scaled growth forms of snow crystals, Crystal Engineering, June 2001, 4 (2–3): 119–129, doi:10.1016/S1463-0184(01)00005-3
web.archive.org
Agricola, Ilka; Friedrich, Thomas, Elementary Geometry, Student mathematical library 43, American Mathematical Society: 96, 2008 [2016-07-21], ISBN 9780821890677, (原始内容存档于2014-01-07).