Dixson, R. J. (1972). Tests and drills in english grammar. Regents.
Lua i Stíl Chicago (17ú heag.)Dixson, Robert J. Tests and Drills in English Grammar. Nueva York: Regents, 1972.
Lua MLA (9ú heag.)Dixson, Robert J. Tests and Drills in English Grammar. Regents, 1972.
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