Wellman G. Guy. (1992). Wordbuilder: Vocabulary development and practice for higher-level students. With answer key. Oxford, Heinemann, 1992.
Παραπομπή σε μορφή Chicago (17η εκδ.)Wellman G. Guy. Wordbuilder: Vocabulary Development and Practice for Higher-level Students. With Answer Key. Oxford, Heinemann, 1992, 1992.
Παραπομπή σε μορφή MLA (9th εκδ.)Wellman G. Guy. Wordbuilder: Vocabulary Development and Practice for Higher-level Students. With Answer Key. Oxford, Heinemann, 1992, 1992.
Πρόσοχή: Οι παραπομπές μπορεί να μην είναι 100% ακριβείς.