LADO, ROBERT. English Language Test for Foreign Students.ROSSI, P. CARLO, S.J. El Inglés de los Estados Unidos.PRATOR, CLIFFORD H. JR. Manual of American English Pronunciation for Adult Foreign Students.WALLACE, BETTY J. The Pronunciation of American English for Teachers of English as a Second Language.FRIES, CHARLES C. The Structure of English, An Introduction to the Construction of English Sentences