C. Fermüller:
"On the Algorithmic Complexity of Vague Descriptions";
in: "Int. Proceedings of Computer Science and Information Technology", F. Hong (ed.); IACSIT Press, Singapore, 2012, ISBN: 978-981-07-1883-1, 39 - 44.
https://publik.tuwien.ac.at/files/publik_207866.pdf