REFERENCES
Allen, W. S. 1947. Living English Structure : A Practice Book of Foreign Student and Key. London : Longmans, Green and Co. Ltd. Frank, M 1972. Modern English : A Practical Reference Guide. New Jersey : Prentice – Hall, Inc. Kaplan, J. P. 1995. English Grammar : Principles and Facts. New Jersey : Prentice Hall International, Inc. Krohn, R. 1972. English Sentence Sructure. Michigan : The University Michigan Press. Murcia, M. C and Freeman, D. L. 1983. The Grammar Book : An ESL/EFL Teacher’s Course. Rowley : NewBury House Publishers, Inc. Nawawi, H. 1998. Metode Penelitian Bidang Sosial. Yokyakarta : Gajah Mada University Press. Popham, W. J. 1967. Educational Statistics. New York : Harper & Row Publisher. Quirk, R. 1972. A Grammar of Contemporary English. England : Longman. Sapir, E. 1949. Language : An Introduction to Study of Speech. New York : Harcourt Bracejava Novich. Thompson, A. J and Martinet, A. V. 1969. A Practical English Grammar. London : The English Language Book Society and Oxford University Press.
78 Universitas Sumatera Utara
Walker, D. J. 1993. Exploring Newspapers. London : Macmillan Publisher Limited. Wren, P. C. and Martin, H. 1983. High School English Grammar and Composition. New Delhi : S. Chad and Company, Ltd. Zandvoort, R. W. 1975. A Handbook of English Grammar. London : ELBS and Longman Group, Ltd. www.insidesumatera.com
79 Universitas Sumatera Utara
