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Chicago Manual of Style 14.193

Foreign-language article and journal titles

Titles of foreign-language articles, like foreign book titles, are usually capitalized sentence-style (see 8.156) but according to the conventions of the particular language (see 14.107). German, for example, capitalizes common nouns in running text as well as in titles (see 11.42). Journal titles may either be treated the same way or, if an author has done so consistently, be capitalized headline-style. An initial definite article (Le, Der, etc.) should be retained, since it may govern the inflection of the following word. Months and the equivalents of such abbreviations as no. or pt. are usually given in English (but see 14.71).

MLA Handbook for Writers of Research Papers by Modern Language Association