anchor.diff:      http://ftp.gnu.org/pub/gnu/
     ];
   
  -  # GnuPG
     gnupg = [
       https://gnupg.org/ftp/gcrypt/
       ftp://ftp.gnupg.org/gcrypt/
  
positive.code:     http://download.savannah.gnu.org/releases/
    ];
  
    # SourceForge
    sourceforge = [
      http://prdownloads.sourceforge.net/
      http://heanet.dl.sourceforge.net/sourceforge/
  
negative.code:     http://cflags.cc/roy/
    ];
  
    sagemath = [
      http://boxen.math.washington.edu/home/sagemath/sage-mirror/src/
      http://mirrors.hustunique.com/sagemath/src/
  