<http://webisa.webdatacommons.org/167860354>	<http://www.w3.org/ns/prov#wasQuotedFrom>	<stanford.edu> .
<http://webisa.webdatacommons.org/prov/17215520>	<http://www.w3.org/ns/prov#wasDerivedFrom>	<http://webisa.webdatacommons.org/167860354> .
<http://webisa.webdatacommons.org/167860354>	<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>	<http://www.w3.org/ns/prov#Entity> .
<http://webisa.webdatacommons.org/167860354>	<http://www.w3.org/ns/prov#value>	"Substantial improvements were produced (see above) even in classes traditionally regarded as necessarily difficult, among them calculus, physics, chemistry, and economics." .