DOC: update documentation links to muparser

Documentation/Cookbook/rst/recipes/improc.rst

@@ -22,7 +22,7 @@ The naming convention “im[x]b[y]” designates the yth band of the xth
 input image.
 
 The *BandMath* application embeds built-in operators and functions
-listed in `muparser documentation <http://muparser.sourceforge.net/mup_features.html#idDef2>`_ thus
+listed in `muparser documentation <https://beltoforion.de/article.php?a=muparser&p=features&s=idDef1#idDef1>`_ thus
 allowing a vast choice of possible operations.
 
 Images with no-data values

Modules/Applications/AppMathParserX/app/otbBandMathX.cxx

@@ -197,7 +197,7 @@ private:
       "into a unique multiband output image."
     );
     SetDocAuthors( "OTB-Team" );
-    SetDocSeeAlso("[1] http://articles.beltoforion.de/article.php?a=muparserx\n\n"
+    SetDocSeeAlso("[1] https://beltoforion.de/article.php?a=muparserx\n\n"
       "[2] BandMath");
     AddDocTag(Tags::Manip);