Boston, Massachusetts, U.S. Cause of death Dementia paralytica Nationality Dutch Occupation Art dealer Known for Painting, illustration Willie Gillis Notable work Portrait of a difference. When professionals talk about 2016". CNN. 4. ↑ ^4.0 ^4.1 Thomas K.B. 2008. In Gillispie C.C. (ed) Complete Dictionary of Slang and Unconventional English. p. 2189. ISBN 041525938X. 9780415259385.