@book{Weiss, author = {Weiss, P.}, title = {Die Ermittlung. Oratorium in 11 Ges{\"a}ngen, Reinbek (Rowohlt Verlag) 1969.}, language = {de} } @book{Weiss, author = {Weiss, P. A.}, title = {Hierarchically Organized Systems in the Theory and Practice, New York (Haffner Publishing Co.) 1971.}, language = {en} }