Hoffmann, Kabanov, Golov, and Proserpio have a thing to say about citations in a recent 15 page Angewandte essay (DOI) 1). The bottom line: do not be lazy citing work and with modern search capabilities there is no excuse really to not being able to find previous work.
Here are some entertaining quotes: "crank papers are recognizable by their lack of citations, or by obsessive selfcitation". It may be interesting to note that Hoffmann limits his self-cites to 11 out of 137 citations. And coming from theoretical chemists: "Computational chemistry and physics at an intermediate level has always been easier than experiment." And this one: "it is wonderful to see an organic synthesis marked not only by a brilliant plan (or a brilliant salvage job once the initial plan went awry)". On search engines: "Google, Bing, Yahoo, Google Scholar, and other search engines are just incredible at unearthing information in the scientific literature, even as they visually crowd the webpage with commercial junk". Could not agree more.
And to make sure at least this blog item has proper citations:
1) R. Hoffmann, A. A. Kabanov, A. A. Golov, D. M. Proserpio, Angew. Chem. Int. Ed. 2016, 55, 10962.