Allen, W. Stannard.1959. Living English structure. London : Longman.
2.
Close, R.A.1962. English as a foreign language. London : G. Allen and Unwin.
3.
. 1975. A reference grammar for students of English. London: Longman.
4.
Dykstra, G., Port, R. and Port, A.1966. Ananse tales. New York: Teachers College Press.
5.
Eckersley, C.E. and Eckersley, J.M.1960. A comprehensive English grammar. London : Longman.
6.
Etherton, A.R.B.1965. Comprehensive English course for Malaysia. Book 3Kuala Lumpur: Longman Malaysia .
7.
Fowler, W.S.1974. Experimenting with multiple choice. English Language Teaching Journal28:2. 145-57.
8.
George, H.V.1962. Teaching 'simple past' and 'past perfect', with notes on related tenses and forms, followed by a grammar of the "past perfect ". Bulletin of the Central Institute of English2. 18-3.
9.
. 1963 . Report on a verb-form frequency count. (Monograph No. 2) Hyderabad: Central Institute of English .
10.
The Guardian Weekly. September 3, 1978.
11.
Hornby, A.S.1954. A guide to patterns and usage in English. London: Oxford University Press.
12.
Jespersen, Otto.1965. A modem English grammar. Part IV. Reprinted. London: G. Allen and Unwin.
13.
Leech, Geoffrey.1971. Meaning and the English verb. London : Longman.
14.
and Svartvik, Jan. 1975. A communicative grammar of English. London: Longman.
15.
Ota, Akira.1963. Tense and aspect of present-day American English . Tokyo: Kenkyusha.
16.
Owen, R.A.1967. Past perfect and simple past. English Language Teaching Journal22:1. 54-59.
17.
Palmer, F.R.1965. A linguistic study of the English verb. London: Longman.
18.
Quirk, Randolph and Greenbaum, Sidney.1973. A university grammar of English . London: Longman.
19.
Rogers, John, Tan, J.C. and Hutton, S.P.1967. College English. Vol. 1. Addis Ababa: Oxford University Press.
20.
Scheurweghs, G.1959. Present-day English syntax. London : Longman.
21.
Tregidgo, P.S.1959. Practical English usage. London : Longman.
22.
Zandvoort, R.W.1966. A handbook of English grammar. 4th ed. London: Longman.