Gap http://www.gap-system.org/
The interface to Singular	http://www-math.science.unitn.it/~costanti/#singular
OpenMath for Gap		http://www-math.science.unitn.it/~costanti/#openmath
This package			http://www-math.science.unitn.it/~costanti/#if


Protocols and standards

There is a list at http://SymbolicNet.org/areas/protocols/
OpenMath http://www.openmath.org/cocoon/openmath//index.html or http://www.openmath.org
and http://www.nag.co.uk/projects/OpenMath/final/final.htm
(there is a Gap package for OpenMath in the Gap CVS repository, for Gap 4.3 and 4.4, and at
http://archives.math.utk.edu/software/multi-platform/gap/deposit/pkg/ , for Gap 4.3)
MP: The Multi Protocol http://SymbolicNet.org/areas/protocols/mp.html
OpenXM (Open message eXchange for Mathematics) http://www.math.kobe-u.ac.jp/OpenXM/ http://www.openxm.org/
MathBus http://www.cs.cornell.edu/simlab/papers/mathbus/mathTerm.htm
MathLink (maybe it's not open) http://www.wolfram.com/solutions/mathlink/



CASes interfaced (but this file could be out-of-date)

SINGULAR http://www.singular.uni-kl.de/
PLURAL http://www.singular.uni-kl.de/plural/
CoCoA http://cocoa.dima.unige.it/
KANT/KASH http://www.math.tu-berlin.de/~kant/kash.html
PARI/GP http://pari.math.u-bordeaux.fr/ http://www.math.u-psud.fr/~belabas/pari/
Risa/Asir http://www.asir.org/
MuPAD http://www.mupad.de/doc.html
Maple http://www.maplesoft.com/
aribas http://www.mathematik.uni-muenchen.de/~forster/sw/aribas.html
Macaulay 2 http://www.math.uiuc.edu/Macaulay2/
Mathematica http://www.wolfram.com/products/mathematica/index.html
Yacas http://yacas.sourceforge.net/


CASes not interfaced, but maybe they could

axiom/aldor http://www.nag.co.uk/symbolic_software.asp http://www.nongnu.org/axiom/ http://www.aldor.org/
fermat http://www.bway.net/~lewis/
felix http://felix.hgb-leipzig.de/
simath/simcalc http://tnt.math.metro-u.ac.jp/simath/index.html
Kan/sm1 http://www.math.kobe-u.ac.jp/KAN/
com.perisic.ring http://ring.perisic.com/
Gb/FGb and RS http://fgbrs.lip6.fr/
polymake http://www.math.tu-berlin.de/polymake/
tcl/tk (not a CAS, but could be useful)
R http://en.wikipedia.org/wiki/R_(programming_language)
Giac/xcas http://www-fourier.ujf-grenoble.fr/~parisse/english.html
Crep http://www.mathematik.uni-bielefeld.de/~sek/crep.html
nauty http://cs.anu.edu.au/~bdm/nauty/
JACAL http://swiss.csail.mit.edu/~jaffer/JACAL
LiE http://wwwmathlabo.univ-poitiers.fr/~maavl/LiE/
LiDIA http://www.informatik.tu-darmstadt.de/TI/LiDIA/
SYNAPS http://www-sop.inria.fr/galaad/logiciels/synaps/
and some programs of http://www.maths.uq.edu.au/~krm/ , that wrote:
http://www.numbertheory.org/calc/krm_calc.html
http://www.numbertheory.org/gnubc/gnubc.html



Lists of CASes

http://web.archive.org/web/20050305091042/http://compalg.inf.elte.hu/compalg/coindex.html
http://web.archive.org/web/20000901055825/www.can.nl/Systems_and_Packages/Per_Purpose/General/index_table.html
http://directory.google.com/Top/Science/Math/Algebra/Software/
http://www-mri.math.kun.nl/systems_and_packages/systems_and_packages.html
http://www.informatik.uni-leipzig.de/~compalg/ca/systems/overview.html
http://web.archive.org/web/20030526114428/http://www.informatik.uni-leipzig.de/~compalg/ca/systems/overview.html
http://www.cs.kun.nl/~freek/digimath/
http://dmoz.org/Science/Math/Software/
http://www.mat.univie.ac.at/~slc/divers/software.html
http://www.lapcs.univ-lyon1.fr/~nthiery/CalculFormelLibre/
http://web.archive.org/web/20030601074816/http://sal.kachinatech.com/A/1/
http://www.medicis.polytechnique.fr/medicis/lien.html
http://orms.mfo.de/about.php



Books of Eric S. Raymond

The Art of Unix Programming http://www.catb.org/~esr/writings/taoup/
The Cathedral and the Bazaar http://www.catb.org/~esr/writings/cathedral-bazaar/



Wikipedia

The interfaced CASes should be added there
http://en.wikipedia.org/wiki/List_of_open-source_software_packages#Math
http://en.wikipedia.org/wiki/Computer_algebra_system
http://en.wikipedia.org/wiki/List_of_abstract_algebra_topics#Computer_algebra



Miscellany

The Rosetta Stone for Computer Algebra Systems:
http://www.univ-orleans.fr/EXT/ASTEX/astex/doc/en/rosetta/html/roset.htm
http://page.axiom-developer.org/zope/mathaction/RosettaStone

Mathematical Knowledge Management Network http://monet.nag.co.uk/mkm/index.html

The SymbolicData Project Tools and Data for Computer Algebra Benchmarks http://www.symbolicdata.org/

Research Institute for Applications of Computer Algebra http://www.riaca.win.tue.nl/

Centre de Calcul MEDICIS (they offer free access to machines with a lot of CASes installed)
http://www.medicis.polytechnique.fr/ http://www.stix.polytechnique.fr/medicis/ri.html

2000 Mathematics Subject Classification http://www.ams.org/msc/

In case that one of these pages is no more available, you can see it with http://www.archive.org/web/web.php

Another interface from Gap to Kant/Kash http://www.gap-system.org/~gap/tmpsite/Packages/alnuth.html

Workshop on Open Source Computer Algebra http://lapcs.univ-lyon1.fr/~nthiery/CalculFormelLibre/report/
