Some reliable sources may not be easily accessible. For example, an online source may require payment, and a print-only source may be available only in university libraries. Rare historical sources may even be available only in special museum collections and archives. Do not reject reliable sources just because they are difficult or costly to access. If you have trouble accessing a source, others may be able to do so on your behalf (see WikiProject Resource Exchange).
Citations to non-English reliable sources are allowed on the English Wikipedia. However, because this project is in English, English-language sources are preferred over non-English ones when available and of equal quality and relevance. As with sources in English, if a dispute arises involving a citation to a non-English source, editors may request that a quotation of relevant portions of the original source be provided, either in text, in a footnote, or on the article talk page. (See Template:Request quotation.)
If you quote a non-English reliable source (whether in the main text or in a footnote), a translation into English should always accompany the quote. Translations published by reliable sources are preferred over translations by Wikipedians, but translations by Wikipedians are preferred over machine translations. When using a machine translation of source material, editors should be reasonably certain that the translation is accurate and the source is appropriate. Editors should not rely upon machine translations of non-English sources in contentious articles or biographies of living people. If needed, ask an editor who can translate it for you.
In articles, the original text is usually included with the translated text when translated by Wikipedians, and the translating editor is usually not cited. When quoting any material, whether in English or in some other language, be careful not to violate copyright; see the fair-use guideline.