**Author details**

Hedda Schmidtke Independent Scientist, Schwerin, Germany

\*Address all correspondence to: schmidtke@acm.org

© 2021 The Author(s). Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/ by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
