Wikipedia is a free source of knowledge, and people are encouraged to reuse content from Wikipedia. There are several publishers that mirror or print Wikipedia content with proper attribution (e.g. Books LLC). However, a few have copied content from Wikipedia without attribution. One problem with this is that it's unethical as the original Wikipedia contributors are not given any credit for their work. But there's another bigger problem: several of these plagiarized articles or books are later added to Wikipedia articles as references, thus introducing the problem of circular references, also known as citogeneses.

The following sources plagiarize content from Wikipedia, and should not be used as references. Please feel free to add to the list, with appropriate revisions of the Wikipedia articles as evidence.

Gyan Publishing / Isha Books / Kalpaz Publications[edit]

Books published by Gyan Publishing / Isha Books / Kalpaz are not WP:RS in general. Several of their books dating to a period before Wikipedia have also been plagiarized from other sources. See discussions at WP:RSN, WT:MIRROR, WT:IN etc.

Their books that are known to have plagiarized content from Wikipedia include:

Gyan books that may be ok

Diamond Pocket Books[edit]

Epitome Books[edit]

A publisher based in New Delhi, probably has some connection with D. K. Agencies, but it is unclear.

Vij Books[edit]

Edtech Press[edit]

Self-published[edit]

Others[edit]

See also[edit]