Copyright by ISIS-Symmetry
Educational institutions are encouraged to reproduce and distribute these materials for educational use free of charge as long as credit and notification are provided. For any other purpose except educational, such as commercial etc, use of these materials is prohibited without prior written permission. Readers may download papers for personal or educational use only, and not for any kind of commercial use. Illustrations can be used only as a part of the papers and by no means can be reused for any purpose without the permission of the owner of the copyrights.