About: http://webisa.webdatacommons.org/204416144

Property	Value
http://www.w3.org/1999/02/22-rdf-syntax-ns#type	http://www.w3.org/ns/prov#Entity
http://www.w3.org/ns/prov#value	The checks should provide an alternating achromatic black and white pattern, which provides the largest evoked potential as compared to other colors, and should have a contrast ratio of at least 60 percent for the best evoked potential.
http://www.w3.org/ns/prov#wasQuotedFrom	google.com