What would be an example of gray literature in scientific research?

Gray literature refers to information that is produced and disseminated outside of traditional publishing and distribution channels. A thesis that has not been published fits this definition because it typically remains accessible only through specific academic institutions or repositories, rather than through widely recognized commercial publishers or peer-reviewed journals.

In contrast, peer-reviewed journal articles are published in scientific journals that undergo formal review processes ensuring quality and credibility. Similarly, a book published by a scientific publisher is widely available and subject to editorial scrutiny, making it part of the traditional literature. Research articles from conference proceedings, although they may be less formal than peer-reviewed journal articles, are also published in organized collections and often indexed, thus falling outside of the gray literature category.

Thus, the thesis stands out as a prime example of gray literature due to its limited dissemination and lack of formal publication status.