Derleth, August
Wisconsin earth: a Sac Prairie sampler / August Derleth
Stanton & Lee, 1948
Buku Teks SO
Diseases of the liver / editor by William T. Foulk
Blakiston Division, McGraw-Hill , 1968
Buku Teks SO
Candlelight di Bundaran HI
Artikel Jurnal
Britannica atlas 1768 / editor, William A. Cleveland
Encyclopaedia Britannica, 1989
Buku Referensi
Britannica atlas 1768 / editor, William A. Cleveland
Encyclopaedia Britannica, 1974
Buku Referensi