Number | Name | Date | Kind |
---|---|---|---|
3699212 | Palm | Oct 1972 | |
4044107 | Houghtaling | Aug 1977 | |
4402923 | Lang | Sep 1983 |
Entry |
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An Article, Productions of Wet-Process Phosphoric Acid, by T. P. Hignett. |
W. R. Parish and J. V. Galluzzo, "A Concept for Wet Grinding Using Pond Water", May 1981. |