1. A chromatic polynomial of a mixed graph;Sotskov;Vestsi Akademii Navuk BSSR Seryya Fizika-Matematychnykh Navuk,1976
2. Reducibility among combinatorial problems;Karp,1972
3. On a circuit-free orientation of mixed graphs;Lambin;Dokladi Akademii Navuk BSSR,1970
4. On an enumeration of circuit-free digraphs generated by a mixed graph;Sotskov;Vestsi Akademii Navuk BSSR Seryya Fizika-Matematychnykh Navuk,1974
5. On one approach to the enumeration of circuit-free digraphs generated by a mixed graph;Sotskov;Vestsi Akademii Navuk BSSR Seryya Fizika-Matematychnykh Navuk,1976