<https://www.codeproject.com/Articles/5298791/Historic-Development-of-Calculus-with-Code>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<https://codeproject.freetls.fastly.net/Articles/5298791/Historic-Development-of-Calculus-with-Code?PageFlow=FixedWidth>