<http://webisa.webdatacommons.org/prov/175028423>	<http://www.w3.org/ns/prov#wasDerivedFrom>	<http://webisa.webdatacommons.org/170285349> .
<http://webisa.webdatacommons.org/170285349>	<http://www.w3.org/ns/prov#wasQuotedFrom>	<questia.com> .
<http://webisa.webdatacommons.org/170285349>	<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>	<http://www.w3.org/ns/prov#Entity> .
<http://webisa.webdatacommons.org/170285349>	<http://www.w3.org/ns/prov#value>	"This book is a step in this empirical direction.23.1.3aThe difference between the exercises in this and other texts is reflected in the absence of answers." .