front page for Wikibook <a href="https://en.wikibooks.org/wiki/de:Mathe_f%C3%BCr_Nicht-Freaks" class="extiw" title="b:de:Mathe für Nicht-Freaks">Mathe für Nicht-Freaks</a>
<a href="//commons.wikimedia.org/wiki/User:Olivier_Vidal" title="User:Olivier Vidal">Olivier Vidal</a>
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