<https://www.cambridge.org/education/subject/english/english-second-language?format=&isbn=9780521140799>
<http://www.w3.org/1999/02/22-rdf-syntax-ns#type>
<http://schema.org/Book>
<https://www.cambridge.org/li/education/subject/english/english-second-language/recycling-english/recycling-elementary-english-key?format=PB&isbn=9780521140799>