Eckersley, C. E., Salisbury, C., & Sharrocks, B. (1968). Essential English for foreign students (Rev. ed., new impression.). Longmans, Green.
Cita Chicago Style (17a ed.)Eckersley, C. E., Charles Salisbury, y Burgess Sharrocks. Essential English for Foreign Students. Rev. ed., new impression. London [etc.]: Longmans, Green, 1968.
Cita MLA (9a ed.)Eckersley, C. E., et al. Essential English for Foreign Students. Rev. ed., new impression. Longmans, Green, 1968.
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