什么是灰色文献（Grey Literature）？
关于灰色文献的定义很多，但许多定义都没有全面概括灰色文献的特点。综合已有文献，笔者归纳出灰色文献的定义并做出相关阐释。
灰色文献通常指不经赢利性出版商控制，而由各级政府、科研院所、学术机构、工商业界等所发布的非秘密的、不作为正常商业性出版物出售而又难以获取的各类印刷版与电子版文献资料。
灰色文献（Grey literature）是相对于白色文献（White literature）和黑色文献（Black literature）而言的。白色文献通常是指公开出版发行且具有国际标准刊号（ISSN）或国际标准书号（ISBN）的正式出版物。黑色文献是指不对外公开、具有完全保密性质的文献。而灰色文献是指介于白色文献与黑色文献之间的文献，虽然已经发行但很难从一般图书销售渠道和常规方式获得。“灰色”文献是一类内容复杂、报道迅速、信息量大、流通范围却较狭窄的情报资料。通常也指一些非公开发表的内部资料，如学术研讨会论文、会议记录科技报告、内部刊物、科研成果等。灰色文献还指一些短暂存留用完后一段时间内就销毁的文献。
灰色文献包括预印本、工作论文、专题论文与学位论文、研究与技术报告、会议论文集、部门及研究中心的时事通讯与公告、基金申请报告、提交给基金机构的反映项目进展的阶段性报告、委员会报告与备忘录、统计报告、技术文件、调查报告、工具手册及宣传册等。
资料链接：关于灰色文献的几个英文定义
The Fourth International Conference on Grey Literature in Washington, DC, in October 1999 defined grey literature as follows: "That which is produced on all levels of government, academics, business and industry in print and electronic formats, but which is not controlled by commercial publishers." In general, grey literature publications are non-conventional, fugitive, and sometimes ephemeral publications. They may include: non-commercial translations, unauthorized copies of works and unauthorized facsimiles of works. Grey literature is generally produced for the purpose of the dissemination of information; it is extremely rare that such material commands a purchase price, except when arriving at second hand dealers.
1 Material that is not commercially published is often referred to as grey literature: Publications produced at all levels by government both in print and electronic formats, but which are not controlled by commercial publishing interests, and where publishing is not the primary business activity of the organization[1].
[1]Grey Literature ’99 Conference. Washington DC (1999). http://www.istl.org/99-fall/conf2.html.
2 Grey literature was for many years synonymous with 'reports literature'. At the turn of the century, documents evolving out of research and development, particularly from the aircraft and aeronautics industries were a very important means of communicating the results of research testing (Augur 1989, 12). One such report from 1915 was called The Behaviour of Aeroplanes in Gusts, the first report written by NASA (Augur 1989, 13). However, it was the onslaught of World War Two which had the greatest impact on report literature, transforming it into "a major means of communication" (Augur 1989, 12).
3 McKimmie, Tim and Joanna Szurmak. 2002. Beyond grey literature: how grey questions can drive research. Journal of Agricultultural and Food Information 4(2):71-79.
The authors define grey literature as materials not identifiable through a traditional index or database. This includes clippings, reports, newsletters, personal files, listserv queries, consultations and personal contacts, and periodicals not cited in databases. Grey literature is an important component of most disciplines and often raise "grey questions" that offer additional approaches to a research agenda. Grey literature fills the information or knowledge gaps that readers do not get from a narrowly focused journal article.
4 Grey literature is literature that has not been formally published.
转载自：http://blog.sciencenet.cn/blog-39523-21494.html
下面是来自维基百科的补充：
https://zh.wikipedia.org/wiki/%E7%81%B0%E8%89%B2%E6%96%87%E7%8D%BB
整理不易...