 
                 Patent Grant
 Patent Grant
                     6416790
 6416790
                    | Number | Name | Date | Kind | 
|---|---|---|---|
| 3893943 | Willard, Sr. | Jul 1975 | A | 
| 4029770 | Willard, Sr. | Jun 1977 | A | 
| Entry | 
|---|
| Werner, C., “McFarland O.5 turbidity standard” in: http://gold.aecom.yu.edu/id/micro/mcfarland.htm, Apr. 1999.* | 
| Biosis abstract, accession No. 1997:397110, 1997. |