1. Aho A. V., Hopcroft J. E., Ullman J. D.: "The Design and Analysis of Computer Algorithms" Addison-Wesley, 1974.
2. Alt H.: "Algorithms for Square Root Extraction" Report A77–12, Fachbereich Angew. Mathematik und Informatik, Saarbrücken, 1977.
3. Alt H.: "Square Rooting is as Difficult as Multiplication" Computing 21, 221–232, (1979).
4. Alt H.: "Functions Equivalent to Integer Multiplication," Report CS-80-8, The Pennsylvania State University, (1980).
5. Borodin A., Munroe I.: "The Computational Complexity of Algebraic and Numeric Problems" Elsevier Comp. Sc. Library, 1975.