About: http://webisa.webdatacommons.org/24575141

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	So using is_numeric() to test for numeric fields and is_alphabetic() to test for fields that can only contain letters is the best alternative for validating those field types.
http://www.w3.org/ns/prov#wasQuotedFrom	sitepoint.com