About: http://webisa.webdatacommons.org/19282856

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	However, when I compile petzold's source code, and run it, all the buttons except for PUSHBUTTON and DEFPUSHBUTTON are white background.
http://www.w3.org/ns/prov#wasQuotedFrom	cprogramming.com