How scientific papers mention grey literature: a scientometric study based on Scopus data

International audience ; Purpose: The purpose of the paper is to provide empirical insight into the use of the term and concept of grey literature in recent scientific papers.Design/methodology/approach: We conducted a scientometric analysis in the Scopus database, on 1,606 papers dealing with grey (or gray) literature and published in 2018. Additionally, we performed a content analysis on a random subsample of 70 papers in open access.Findings: The part of papers dealing with grey literature is low (0.05%) but steadily rising. They are from over 100 countries and a long tail of institutions, covering namely medical and health sciences and related topics. The dominant document type is systematic reviews, defining grey literature generally thought of as “unpublished”, “not peer reviewed” and “not in databases” and meaning most of the time all kinds of reports and conference papers. A large variety of sources and options how to retrieve grey literature is mentioned, including Google and Google Scholar, specialized digital libraries, relevant websites, handsearching in bibliographic references and contact with experts in the field.Research limitations/implications: The study is limited to papers indexed in the Scopus database, mainly journals, written in English, with a bias in favor medical and life sciences.Originality/value: There is no recent study on the real usage of the term of grey literature in a large sample of academic papers.