1. Double-effect, triple-effect and quadruple-effect absorption machines;Alefeld,1983
2. Altenkirch, E., Tenckhoff, B., Absorptionskaeltemaschine zur kontinuierlichen Erzeugung von Kaelte und Waerme oder acuh von Arbeit., in, Germany, 1914.
3. An evaluation of a rankine cycle driven heat pump;Christensen;Heat Recovery Syst. CHP,1990
4. Comparative simulation and investigation of ammonia-water: absorption cycles for heat pump applications;Engler;Int. J. Refrig.,1997
5. Branched GAX cycle gas fired heat pump;Erickson,1996