Journal of Combinatorial Theory, Series A Volume 33, Issue 1, July 1982, Pages 48-64 doi:10.1016/0097-3165(82)90078-4block mapの性質。

Enrico Formenti and Petr Kůrka 2007 Nonlinearity 20 105 http://iopscience.iop.org/0951-7715/20/1/007/ doi: 10.1088/0951-7715/20/1/007Non-sofic attractor の存在。