6Danila N. Heat production in co-generation plants and its transport over large distances[C]// Proceedings of the Symposium with International Participation on Energy Conservation and International Cooperation. Bucharest, Rom. 1982: 89-96.
7Zsebik A. Heat exchanger connection in substations-a tool of decreasing return temperature in district heating networks [J]. Energy Engineering, 2001, 98(5) : 20 - 28.
8SONG Zhiping. Total energy system analysis of heating [J]. Energy (Oxford), 2000, 25(9) : 807 - 822.
