1. Heizanlage zur Übertragung der Energie aus Sonnenkollektoren;Gützold,1980
2. Arrangements for the transfer of heat from an upper level to a lower level;Tacchi,1980
3. Device for passive heat transport;De Beni,1982
4. Proc. Passive and Hybrid Solar Energy Update Meet.;Hedstrom,1983
5. INTERSOL '85;Neeper,1985