Wikipedia:Offline sources

Books are a typical example of an offline source. These are often great resources for history, philosophy and literature, and they often contain information that can't be found online. Several ongoing projects, such as Project Gutenberg, Internet Archive, NLA Trove and Google Book Search, aim at digitizing certain books or newspaper articles and presenting them online. Even if the books are online, it might be necessary to consult a print edition to double-check any errors from the OCR scanning.

Many academic journals only make short abstracts available online. Other content providers, like The Wall Street Journal, publish their content behind a paywall that prevents non-subscribers from accessing the content. Other websites, like the Philadelphia Inquirer, only publish their content online for a few weeks. Sometimes a source was once online, but now is offline (link rot).

Special care should be taken when using offline sources. Provision of full bibliographic information helps Wikipedia's readers and editors find the source when they need it, and also increases the source's credibility as a reliable source. This is often done by using a fully-filled out citation template such as {{cite book}} or {{cite news}}. Use of the quote= parameter within those citation templates provides some context for the reference. This is especially important when using the off-line source to support a fact that might be controversial or is likely to be challenged. Providing identifiers such as an ISBN, OCLC number, Open Library number or similar can help others locate physical copies, as cataloguing data can often vary from one library to another.

Many offline sources are easier than you might think to find online. The Internet Archive full text search, as well as Internet Archive Scholar, are often able to provide a copy or snippet from millions of academic papers, books and even TV programs.

Sometimes, the use of an offline source will be challenged. Be sure to assume good faith for the user who cited the offline source. They might even be able to provide you a scan or an excerpt from that source. Consider visiting your local library to obtain a copy. Even if the library doesn't have that particular book or journal article, it might be available through interlibrary loan. Also consider posting an inquiry on the relevant WikiProject, because some interested editors might have a copy of that source. The volunteers at WikiProject Resource Exchange might be able to help you coordinate your search.

• FUTON bias
• Wikipedia:Resource requests
• Wikipedia:Link rot
• Wikipedia:Reliable sources/Cost
• Wikipedia:Offline sources only, arguments to avoid in deletion discussions