French, P., Langford, D., & Langford, D. [ca. 1993]. Varieties of English : An Introduction to the Study of Language. In Supplementary Textbooks (2 nd ed) [Cd]. London: Bloomsbury Academic. https://doi.org/10.1007/978-1-349-22723-5

FRENCH, Peter, LANGFORD, David und LANGFORD, David., 1993. Varieties of English : An Introduction to the Study of Language. 2 nd ed. London: Bloomsbury Academic. ISBN 9781350483903.

French, P., D. Langford, und D. Langford. „Varieties of English : An Introduction to the Study of Language“. Supplementary Textbooks, 2 nd ed, cd, Bloomsbury Academic, 1993, https://doi.org/10.1007/978-1-349-22723-5.

French, Peter/Langford, David/Langford, David.: Varieties of English : An Introduction to the Study of Language, 2 nd ed. Aufl. London 1993.

French, P., Langford, D. und Langford, D. (1993), Varieties of English : An Introduction to the Study of Language, Supplementary Textbooks, 2 nd ed., Bd. , Bloomsbury Academic, London, verfügbar unter:https://doi.org/10.1007/978-1-349-22723-5.