by Boesch, F., McHugh, J.
Published in IEEE transactions on circuits and systems (01.05.1974)

by Di Battista, Giuseppe, Tamassia, Roberto, Vismara, Luca
Published in Information and computation (25.08.2001)

by Nievergelt, J, Deo, Narsingh
Published in Information processing letters (29.09.1995)

by Voblyi, V. A.
Published in Journal of mathematical sciences (New York, N.Y.) (22.12.2023)