https://arxiv.org/abs/1212.0638 explains an experiment leading to an increase of 774 citations in 129 papers basically as they
created a fake researcher (Marco Alberto Pantani-Contador — a reference to two infamous cyclists, Marco Pantani and Alberto Contador, each of whom was accused of blood doping). Copying and pasting text from a website, adding a few figures and graphs and lots and lots of self-citations … created six fake documents, translated them into English using Google Translate, and uploaded them to a new webpage under their university’s domain. It was a process, the authors explain, that took less than half a day’s work.