Admoni, Wladimir
Munchen Beck 1982
Buku Teks
Dornseiff, Franz, author
Walter De Gruyter and co, 1959
Buku Referensi
Reimann, Brigitte
Berlin Aufbau 1963
Buku Teks
Harberts, DW
Amsterdam Meulenhoff 1948
Buku Teks
Erben, Johannes, author
Munchen Max Hueber 1980
Buku Teks