From the webpage:
The Defense Technical Information Center (DTIC®) serves the DoD community as the largest central resource for DoD and government-funded scientific, technical, engineering, and business related information available today .
For more than 65 years DTIC has provided the warfighter and researchers, scientists, engineers, laboratories, and universities timely access to over 2 million publications covering over 250 subject areas. Our mission supports the nation’s warfighter.
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The United States government and I suspect other national governments has sponsored decades worth of research on text processing, mining and evaluation. This is one of the major interfaces to US based literature. The Literature-Related Discovery (LRD) material originated from this source.
You will find things such as: “Research in Information Retrieval – Final Report – An investigation of the techniques and concepts of information retrieval,” dated 31 July 1964 as well as current reports.
A real treasure trove of historical and current material on information retrieval. The historical material will help you recognize when you are re-solving a well known problem. And sometimes help you avoid repeating old mistakes.