%% -*-BibTeX-*- @Article{GroetschelWakabayashi1980, author = "Martin Gr{\"o}tschel and Yoshiko Wakabayashi", title = "Hypohamiltonian digraphs", journal = "Methods of Operations Research", volume = "36", pages = "99--119", year = "1980", classmath = "*05C38 05C20 05C45", language = "English", }