Note! Computer Algebra Group page
Here are links to the packages implementing some of the algorithms by S.A. Abramov:
1. LFsys package implementing EG-eliminations. Implemented by Denis Khmelnov. Supported in part by the RFBR and INTAS under Grant 95-IN-RU-412
2. Slode package implementing algorithms to construct some special power series solutions of linear ordinary differential equations with polynomial coefficients. Implemented by Anna Ryabenko. Supported in part by the RFBR and INTAS under Grant 95-IN-RU-412
Other sources:
4. Computer Algebra Information Network