“Reference rot in web-based scholarly communication”…

“[In a sample of] 3.5 million scholarly articles published between 1997 and 2012 [there is an] alarming link rot ratio for all three corpora: 13% of arXiv, 22% of Elsevier, and 14% of PMC articles published in 2012 suffer from link rot. These numbers only increase for older articles, for example, for articles published in 2005 the corresponding numbers are 18%, 41%, and 36%.”