{"has_more":true,"total_items":9,"items":[{"vg_id":0,"journal":"even if market boundaries are often blurry and market power often eludes quantification. The use of \"direct evidence\" to prove anti-competitive effects in American Express illustrates why"},{"vg_id":0,"journal":"Since Visa and MasterCard were also raising their merchant fees over the same period, it seems at least plausible that the JCB card, which issued cards in several U.S. states until 2018 but had a trivial share of GPCC card volume, 52 also raised its merchant fees"},{"vg_id":0,"authors":[{"author_name":" Id"}]},{"vg_id":0,"authors":[{"author_name":"See Wikipedia"},{"author_name":" Co"},{"author_name":" Ltd"}],"doi":"https://doi.org/10.1093/ww/9780199540884.013.u6363"}]}