@articleSteffen_Wolf_2022, title=Even Factors in Edge-Chromatic-Critical Graphs with a Small Number of Divalent Vertices, volume=38, DOI=10.1007/s00373-022-02506-x, number=3104, journal=Graphs and Combinatorics, publisher=Springer Science and Business Media LLC, author=Steffen, Eckhard and Wolf, Isaak Hieronymus, year=2022 

@articleKlopp_Steffen_2021, title=Fractional Matchings, Component-Factors and Edge-Chromatic Critical Graphs, DOI=10.1007/s00373-020-02266-6, journal=Graphs and Combinatorics, author=Klopp, Antje and Steffen, Eckhard, year=2021, pages=559–580