Jeffrey Beall has published "What I Learned from Predatory Publishers" in Biochemia Medica.
Here's an excerpt:
This article is a first-hand account of the author’s work identifying and listing predatory publishers from 2012 to 2017. Predatory publishers use the gold (author pays) open access model and aim to generate as much revenue as possible, often foregoing a proper peer review. The paper details how predatory publishers came to exist and shows how they were largely enabled and condoned by the open-access social movement, the scholarly publishing industry, and academic librarians. The author describes tactics predatory publishers used to attempt to be removed from his lists, details the damage predatory journals cause to science, and comments on the future of scholarly publishing.