Number | Name | Date | Kind |
---|---|---|---|
2944956 | Blue et al. | Jul 1960 | |
3477938 | Kircher | Nov 1969 | |
3674676 | Fogelman | Jul 1972 | |
3796648 | Conner, Jr. et al. | Mar 1974 | |
3809630 | DeNora et al. | May 1974 |
Number | Date | Country |
---|---|---|
700,296 | Dec 1964 | CA |
Entry |
---|
"New Ion Exchange Membrane Vital in Disinfecting Sewage," Product Information Service, DuPont & Co., 12/72. |