Bibliographical research

Many years ago, before the Internet and the introduction of the electronic publications, bibliographical research was conducted in physical libraries, and the most commonly used source of information was the regularly updated Index Medicus, a multi-volume treatise that for 125 years summarized and indexed all published medical literature, classifying it by keywords and subject headings. And whenever researchers or clinicians needed to read the indexed article that was not available in their library, they would mail the corresponding author a request for a reprint. Academic courtesy has routinely been shown by sending paper reprints to all those who requested them, regardless of where in the world such requests would come from.