1. European Commission: Europeans and their languages. Special Eurobarometer 386 (2012)
2. Poplack, S.: Sometimes I’ll start a sentence in Spanish Y TERMINO EN ESPANOL: toward a typology of code-switching. Linguistics 18, 581–618 (1980)
3. Claeser, D., Felske, D., Kent, S.: Token-level code-switching detection using Wikipedia as a lexical resource. In: Rehm, G., Declerck, T. (eds.) GSCL 2017. Language Technologies for the Challenges of the Digital Age. Lecture Notes in Artificial Intelligence, Lecture Notes in Computer Science, vol. 10713, pp. 192–198. Springer, Heidelberg (2018)
4. Johnson, S.: A dictionary of the english language: a digital edition of the 1755 classic. In: Besalke, B. (ed.) The History of the English Language. https://johnsonsdictionaryonline.com/the-history-of-the-english-language/. Accessed 15 April 2014
5. Muysken, P.: Code-switching and grammatical theory. In: Milroy, L., Muysken, P. (eds.) One Speaker, Two Languages: Cross-Disciplinary Perspectives on Code-Switching, pp. 177–198. Cambridge University Press, Cambridge (1995)