1. Intermediate concentration solar thermal collectors;Rabl,1981
2. Development of solar collectors for low temperature level of concentrators for thermal and photovoltaic conversions;Kleinwachter,1978
3. Paraboloid simple and compound cone concentrators for spherical absorbers;Tully;Solar Energy,1982
4. A recurrence relation for calculation of sections of compound conical concentrators;Hassib,1982