Vollmar, H.F.A. (Hendrik Frederik Arnold), author
H.D.Tjeenk Willink and Zoon N.V., 1950
Buku Teks
Heynderickx, Priscilla, author
Lessius Hogeschool, 2001
Buku Teks
Vollmar, H.F.A. (Hendrik Frederik Arnold), author
H.D. Tjeenk Willink & Zoon, 1946
Buku Teks
Heestermans, Hans, author
Thomas Rap, [Date of publication not identified]
Buku Referensi
Santen, Ariane van, author
Foris, 1984
Buku Teks