https://elibrary.klett-cotta.de/article/10.21706/ps-79-7-539 https://elibrary.klett-cotta.de/article/10.21706/ps-79-7-566 https://elibrary.klett-cotta.de/article/10.21706/ps-79-7-594 https://elibrary.klett-cotta.de/article/10.21706/ps-79-7-623