1. Refrigerating and Airconditioning Engineers (ASHRAE);American Society and Heating;Handbook of Fundamentals,1972
2. Analytical and empirical investigation of the effective thickness of the atmosphere; a new formula for air mass;Nijegorodov,1995
3. ASHRAE model empirical coefficients to estimate solar radiation on a clear in Botswana;Nijegorodov,1995