1. Keldysh, L.V.: Diagram technique for nonequilibrium processes. Zh. Eksp. Teor. Fiz. 47, 1515 (1964)
2. Keldysh, L.V.: Diagram technique for nonequilibrium processes. Sov. Phys. JETP 20, 1018 (1965)
3. Bonitz, M. (ed.): Progress in Nonequilibrium Green’s Functions. World Scientific, Singapore (2000)
4. Bonitz, M., Semkat, D. (eds.): Progress in Nonequilibrium Green’s Functions II. World Scientific, Singapore (2003)
5. Bonitz, M., Filinov, A. (Eds.): Progress in Nonequilibrium Green’s Functions III. In: Journal of Physics: Conference Series, vol. 35. (2006)