An earlier study that addressed the scope of all published works: J-B Michel, et al. "Quantitative Analysis of Culture Using Millions of Digitized Books". Scie

An earlier study that addressed the scope of all published works: J-B Michel, et al. "Quantitative Analysis of Culture Using Millions of Digitized Books". Science (the journal) (16 Dec 2010). https://www.science.org/doi/10.1126/science.1199644 https://www.science.org/doi/10.1126/science.1199644 Their focus was on words but along the way they analyzed the number of published texts, a study that "includes serials and sets but excludes kits, mixed media, and periodicals such as newspapers". They concluded that the world had published 129 million "editions" (one book may have multiple editions).