1. Granryd E. Royal Institute, Stockholm, personal communication.
2. Swedish Heat Pump Association (Svenska Varmepumpfbreningen, SVEP).
3. IEA, Heat Pumping Technologies, Annex 21: industrial heat pumps — experiences, potential and global environmental benefits, 1995.
4. Hallén T. Akademiska Hus, Gothenburg, Sweden, personal communication.
5. Hogberg M. Non-azeotropic mixtures as working fluids in heat pumps: a theoretical and experimental study. PhD thesis, 1995.