Thomas Zaslavsky Signed graphs: To: T. Zaslausky, Discrete Appl. Math 4 (1982) 47-74. 248 1983 5 Discret. Appl. Math. 2 https://doi.org/10.1016/0166-218X(83)90047-1 db/journals/dam/dam5.html#Zaslavsky83