Kernels in a special class of digraphs.

Hortensia Galeana-Sánchez Xueliang Li Kernels in a special class of digraphs. 73-80 1998 178 Discrete Mathematics 1-3 http://dx.doi.org/10.1016/S0012-365X(97)81818-3 db/journals/dm/dm178.html#Galeana-SanchezL98