Baker, M. Dryson equations, Ward identities, and the infrared behavior of Yang-Mills theories. [Schwinger-Dyson equations, Slavnov-Taylor identities], article, January 1, 1979; (https://digital.library.unt.edu/ark:/67531/metadc1098728/m1/1/: accessed April 20, 2019), University of North Texas Libraries, Digital Library, digital.library.unt.edu; .