Wow - did a search of PubMed Central for the keyword HeLa because Rebecca Skloot is here today to talk about her book "The immortal Life of Henrietta Lacks" which is about the woman behind the HeLa cells.
And there are a wopping 47170 papers in PMC that come up. I am sure some of these will be not about HeLa cells but most seem to be.
Here is a link to the results: hela - PMC Results
That's pretty incredible - 47000 or so papers, freely available, all with some reference to this one human cell line.