en Hilton, Peter; Pedersen, Jean (), „Symmetry in mathematics”, Computers & Mathematics with Applications, 12 (1-2): 315–328, doi:10.1016/0898-1221(86)90157-4, MR0838152
en Hilton, Peter; Pedersen, Jean (), „Symmetry in mathematics”, Computers & Mathematics with Applications, 12 (1-2): 315–328, doi:10.1016/0898-1221(86)90157-4, MR0838152
en Janner, Aloysio (iunie 2001), „DNA enclosing forms from scaled growth forms of snow crystals”, Crystal Engineering, 4 (2–3): 119–129, doi:10.1016/S1463-0184(01)00005-3