Harary, Frank. 1953. On the Notion of Balance of a Signed Graph. Michigan Mathematical Journal 2(2). 143–146.
@article{Harary1953, author = {Harary, Frank}, journal = {Michigan Mathematical Journal}, number = {2}, pages = {143–146}, title = {On the Notion of Balance of a Signed Graph}, volume = {2}, year = {1953} }