| 162 / | HD | PAPER MAKING AND FIBER LIBERATION |
| 1 | DF | PROCESSES OF CHEMICAL LIBERATION, RECOVERY OR PURIFICATION OF NATURAL CELLULOSE OR FIBROUS MATERIAL {33} |
| 70 | DF | .~ Treatment with particular chemical {9} |
| 72 | DF | .~.~ Organic {5} |
| 74 | | .~.~.~ Chlorine containing |