Copyright notice

The text in these pages is written by us. However, it is very hard to avoid wordings, constructs or even whole sentences which are consistently repeated in literature, or are perfectly phrased by some other author. Whereever practical, we took care to include references to other authors. If we failed to do so in a place or two, it was not by intention to appropriate someones intellectual property, and please do draw our attention to this fact. We systematically check the content of these pages with anti-plagiarism tools like CopyGator, PlagiarismSoftware, Small SEO Tools and The Plagiarism Checker.

Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported License Material in these pages is intended for free, public use. It can be copied, printed, cited and linked without explicit permission of the authors for personal use or further education provided it is for non-profit purpose. It is expected to credit the authors if portions of text are used elsewhere. Any commercial or for-profit use is only possible with prior, written permission from authors.