\begin{thebibliography}{8}
\expandafter\ifx\csname natexlab\endcsname\relax\def\natexlab#1{#1}\fi
\expandafter\ifx\csname url\endcsname\relax
  \def\url#1{\texttt{#1}}\fi
\expandafter\ifx\csname urlprefix\endcsname\relax\def\urlprefix{URL }\fi

\bibitem[{Berka and Kreiser(1973)}]{logiktexte}
Berka, K., Kreiser, L. (Eds.), 1973. {Logik-Texte -- Kommentierte Au\esi wahl
  zur Geschichte der modernen Logik}. Akademie-Verlag, \Berlin, \nth
  2\,\rev\,\ed\ (\nth 1\,\ed\,1971; \nth 4\,\rev\,\rev\,\ed\,1986).

\bibitem[{Bussotti(2006)}]{From-Fermat-to-Gauss}
Bussotti, P., 2006. {From \fermat\ to \gauss: indefinite descent and methods of
  reduction in number theory}. No.~55 in Algorismus. \Dr\ Erwin Rauner Verlag,
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\bibitem[{Di~Leonardo and Marino(2001)}]{strange-pieri}
Di~Leonardo, M.~V., Marino, T., 2001. Il principio del minimo interio \`e
  equivalente al principio di induzione completa? Quaderni della riceria in
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\newline\urlprefix\url{http://math.unipa.it/~grim/pieri3.pdf}

\bibitem[{Fermat(1891\ff)}]{fermat-oeuvres}
Fermat, P., 1891\ff. \OE uvres de \fermat. {\gauthiervillars}, \Ed\ by Paul
  Tannery, Charles Henry.
\newline\urlprefix\url{http://fr.wikisource.org/wiki/%C5%92uvres_de_Fermat}

\bibitem[{Heyting(1930)}]{heyting-1930-logic}
Heyting, A., 1930. {Die formalen Regeln der intuitionistischen Logik}.
  {Sitzung\esi berichte der Preu\sz i\-schen Akademie der Wissenschaften,
  \Berlin, Physikalisch-mathematische Klasse II} 1930, 42--56, short version
  also in: \cite{logiktexte}, \PP{173}{178}.

\bibitem[{Pieri(1907)}]{pieri}
Pieri, M., 1907. Sopra gli assiomi aritmetici. Il Bollettino dell'Accademia
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\bibitem[{Wirth(2004)}]{wirthcardinal}
Wirth, C.-P., 2004. {{\em\DescenteInfinie} + {Deduction}}. Logic J. of the IGPL
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\newline\urlprefix\url{http://www.ags.uni-sb.de/~cp/p/d}

\bibitem[{Wirth(2006)}]{fermatsproof}
Wirth, C.-P., 2006. A Self-Contained and Easily Accessible Discussion of the
  Method of Descente Infinie and Fermat's Only Explicitly Known Proof by {\em
  Descente Infinie}. {SEKI-Working-Paper SWP--2006--02 (ISSN 1860--5931)}.
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\newline\urlprefix\url{http://www.ags.uni-sb.de/~cp/p/fermatsproof}

\end{thebibliography}
