Chudnovsky, MariaMaffray, FrédéricSeymour, PaulSpirkl, Sophie2022-08-122022-08-122018-07https://doi.org/10.1016/j.jctb.2018.01.003http://hdl.handle.net/10012/18532The final publication is available at Elsevier via https://doi.org/10.1016/j.jctb.2018.01.003 © 2018.. This manuscript version is made available under the CC-BY-NC-ND 4.0 license http://creativecommons.org/licenses/by-nc-nd/4.0/Let G be a Berge graph such that no induced subgraph is a 4-cycle or a line-graph of a bipartite subdivision of K4. We show that every such graph G either is a complete graph or has an even pair.enAttribution-NonCommercial-NoDerivatives 4.0 Internationalhttp://creativecommons.org/licenses/by-nc-nd/4.0/perfect graphsberge graphssquare-freeprismseven pairsArticle