Padron:Springer
Hazewinkel, Michiel, pat. (2001), "Springer", Encyclopedia of Mathematics, Springer, ISBN 978-1556080104{{citation}}: CS1 maint: date auto-translated (link)
Hazewinkel, Michiel, pat. (2001), "Springer", Encyclopedia of Mathematics, Springer, ISBN 978-1556080104{{citation}}: CS1 maint: date auto-translated (link)