<http://webisa.webdatacommons.org/99993981>	<http://www.w3.org/ns/prov#wasQuotedFrom>	<purplemath.com> .
<http://webisa.webdatacommons.org/99993981>	<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>	<http://www.w3.org/ns/prov#Entity> .
<http://webisa.webdatacommons.org/99993981>	<http://www.w3.org/ns/prov#value>	"Matrices are very messy, especially if you are doing them by hand, and notes can make it easier to check your work later." .
<http://webisa.webdatacommons.org/prov/301585914>	<http://www.w3.org/ns/prov#wasDerivedFrom>	<http://webisa.webdatacommons.org/99993981> .