Verbaan, P., van Leeuwen, J., Wiedermann, J. Complexity of Evolving Interactive Systems. In: KARHUMÄKI, J., MAURER, H., PAUN, G., ROZENBERG, G., eds. Theory is Forever. Essays Dedicated to Arto Salomaa on the Occasion of his 70th Birthday. Berlin: Springer, 2004, s. 268-281. Lecture Notes in Computer Science, 3113. ISBN 3-540-22393-2. Dostupné z: https://doi.org/10.1007/978-3-540-27812-2_24