In 1998 Holland Cotter estimated "only two dozen or so paintings...attributed...with varying degrees of confidence, along with some drawings and a few pages from...the Turin-Milan Hours". See Mysteries in the Crystalline World of a Flemish Master, 24 April 1998. There is a complex relationship and tension between art historians and holding museums in assigning authorship. Of the 40 or so works considered originals in the mid 80s, around ten are now vigorously contested by leading researchers as workshop
