Research on Korean free dailies
On the Resources page, a link to a article in the Journal of Media Management on free and paid newspapers in Korea: “What to Read in the Morning? A Niche Analysis of Free Daily Papers and Paid Papers in Korea” by Keunyeong Yi and Yoontaek Sung.
They argue on the basis of analyzing readership and circulation data, on a survey, that free dailies have cannibalized on paid and sports papers, and could be even more harmful to the latter category.