(1987): Breadth and depth vocabulary knowledge: implications for acquisition and instruction. In: McKeown, M and M Curtis (eds) The Nature of Vocabulary Acquisition. Hillsdale, NJ. : Lawrence Erlbaum Associates.
WILLIS, F. , G. DOBLE , U. SANKARAYYA and A. SMITHERS
(1977): Residence abroad and the student of modern languages. Bradford: University of Bradford Modern Languages Centre.
YOSHIDA, M.
(1978): The acquisition of vocabulary by a Japanese speaking child. In: E Hatch (ed). Second Language Acquisition: a book of readings. Rowley, Mass.: Newbury House.