About: http://webisa.webdatacommons.org/1951659

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	Furthermore, the validity of the results from included studies was hampered by high attrition rate, absence of control groups, and failure to control for confounding variables such as exposure to other treatments.
http://www.w3.org/ns/prov#wasQuotedFrom	york.ac.uk