| 528 / | HD | SYNTHETIC RESINS OR NATURAL RUBBERS -- PART OF THE CLASS 520 SERIES |
| * | DD | SYNTHETIC RESINS (Class 520, Subclass 1) {23} |
| 44 | DF | .~ FROM REACTANT HAVING AT LEAST ONE -N=C=X GROUP (WHEREIN X IS A CHALCOGEN ATOM) AS WELL AS PRECURSORS THEREOF, E.G., BLOCKED ISOCYANATE, ETC. {17} |
| 76 | DF | .~.~ With ether or thioether compound containing at least two -C-X-C- groups {3} |
| 79 | | .~.~.~ Ether or thioether contains a carbocyclic or aromatic group |