1. de Bruijn, N.G.: Acknowledgement of priority to C. Flye Sainte-Marie on the counting of circular arrangements of
$$2^n$$
2
n
zeros and ones that show each
$$n$$
n
-letter word exactly once. Technical report. (EUT report. WSK, Department of Mathematics and Computing Science), vol. 75-WSK-06, Technische Hogeschool Eindhoven, Netherlands (1975)
2. Cassaigne, J., Karhumäki, J., Puzynina, S., Whiteland, M.A.:
$$k$$
k
-abelian equivalence and rationality. Fundamenta Informaticae 154(1–4), 65–94 (2017)
3. Lecture Notes in Computer Science;J Cassaigne,2016
4. Cassaigne, J., Karhumäki, J., Saarela, A.: On growth and fluctuation of
$$k$$
k
-abelian complexity. Eur. J. Comb. 65(Suppl C), 92–105 (2017)
5. Eilenberg, S.: Automata, Languages, and Machines, vol. A. Academic Press Inc., New York (1974)