Humphreys, G. (1976). English grammer. Hodder & Stoughton.
Lua i Stíl Chicago (17ú heag.)Humphreys, Gordon. English Grammer. London: Hodder & Stoughton, 1976.
Lua MLA (9ú heag.)Humphreys, Gordon. English Grammer. Hodder & Stoughton, 1976.
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