1. Zoller F. Hollow pane of glass. German patent 387655; 1924.
2. Kirlin I.M. Insulating pane. US patent 1370974; 1921.
3. Chalons F.R. Transparent insulating panel. French patent 2294315; 1976.
4. Falbel G. Evacuated dual glazing system. US patent 3990201; 1976.
5. Rowe. Insulating materials. US patent 3936553; 1976.