Four Decades of Materials are Used by Researchers in Mathematics: Evaluating Citations' Age and Publication Types in Mathematical Research

The purpose of this article was to re-test previous findings that forty years of mathematics research is required to cover 90 percent of the mathematics citations. I have used an improved comprehensive methodology, extracting all articles by the University of British Columbia department of mathematics for 2011 and working with the 4,161 citations from these articles. The results confirm previous research that we need forty years of mathematics research to cover 90 percent of the materials cited by mathematics faculty. Also, I have found that in mathematics only 24 percent of citations are coming from research newer than five years. Moreover, I report that the vast majority of the mathematics citations are from journals—81 percent are journal articles, while only 15 percent are books citations.