b.newTwig("placeOfPublication").with(b.newNode("Cambridge")).toString(),
b.newTwig("publisher").with(b.newNode("Cambridge Scholars")).toString(),
b.newTwig("subject").with(b.newNode("Environmental")).toString(),
b.newBoolean().with(b.newTwig("subject").with(b.newNode("Environmental")))
.with(b.newTwig("issued").with(b.newNode("2009"))).toString(),
b.newTwig("type").with(b.newNode("text"))
.with(b.newNode("monographic")).toString(),
b.newTwig("identifier").with(
// here, twig with empty root node to represent first nested entity node
b.newTwig().with(b.newTwig("id").with(b.newNode("9780852935392")))
.with(b.newTwig("type").with(b.newNode("isbn")))