Jean Berstel Luc Boasson Olivier Carton Isabelle Fagnot A First Investigation of Sturmian Trees. 73-84 2007 conf/stacs/2007 STACS http://dx.doi.org/10.1007/978-3-540-70918-3_7 db/conf/stacs/stacs2007.html#BerstelBCF07