1. Atkinson, M.D.: The Complexity of Algorithms. In: Computing Tomorrow: Future Research Directions in Computer Science, pp. 1–20. Cambridge, Univ. Press, New York (1996)
2. Brassard, G., Bratley, P.: Fundamentals of Algorithms. Prentice Hall (1996)
3. Castro-Company, F., Romaguera, S., Tirado, P.: An Application of the Banach Contraction Principle on the Product of Complexity Spaces to the Study of Certain Algorithms with Two Recurrence Procedures. In: Vigo-Aguiar, J. (ed.) Proceedings of the 2010 International Conference on Computational and Mathematical Methods in Science and Engineering (CMMSE 2010), Almería, Spain, vol. 5, pp. 978–984 (2010) ISBN 978-84-613-5510-5
4. Castro-Company, F., Romaguera, S., Tirado, P.: Application of the Banach Fixed Point Theorem on Fuzzy Quasi-Metric Spaces to Study the Cost of Algorithms with Two Recurrence Equations. In: IJCCI 2010 2nd International Joint Conference on Computational Intelligence (2010) ISBN 978-989-8425-32-4
5. Cho, Y.J., Grabiec, M., Radu, V.: On non Symmetric Topological and Probabilistic Structures. Nova Sci. Publ. Inc., New York (2006)