1. Anon. (1993 ) , Washington DC, National Academy of Science, USA.
2. Standard Solutions for Humidity Control at 25° C.
3. The American Society for Testing and Materials (1976 )Standard Recommended Pradice for Maimaining Constam Relative Humidity by Means of Aqueous Solutions, ASTM Designation E, 104-51 (Reapproved 1971), pp.609 -612 .