@book{Kayser, author = {Kayser, H.}, title = {Akr{\´o}asis. Die Lehre von der Harmonik der Welt, Basel (Benno Schwabe Verlag) 1946.}, language = {de} } @book{Kayser, author = {Kayser, H.}, title = {Orphikon, Basel (Schwabe \& Co. Verlag) 1973.}, language = {de} }