Ralf Hillebrand*, Frank Postel (Germany), tonner@plato.uni-paderborn.de Flexible Mathematical GUI Controls for Mathematical Electronical Documents The MuPAD Group develops mathematical software components which may be used as plugins in other software packages: An editor for input and output of mathematical expressions, a Control for mathematical computations based on MuPAD and a graphics tool for visualization and manipulation of three-dimensional objects. These Controls can be integrated into presentation tools such as Microsoft PowerPoint, Internet Browsers or professional authoring tools such as Toolbook, Director or Authorware. The Control for mathematical computations combines the power of a computer algebra system with the demand for special user interfaces for educational purposes. The target group of these Controls are authors and publishers of electronical mathematical documents.