Template:Springer
Hazewinkel, Michiel, ed. (2001), “Springer”, Encyclopaedia of Mathematics, Springer, ISBN 978-1-55608-010-4
Hazewinkel, Michiel, ed. (2001), “Springer”, Encyclopaedia of Mathematics, Springer, ISBN 978-1-55608-010-4, http://eom.springer.de/default.htm