528 / | HD | SYNTHETIC RESINS OR NATURAL RUBBERS -- PART OF THE CLASS 520 SERIES |
* | DD | SYNTHETIC RESINS (Class 520, Subclass 1) {23} |
422 | .~ NITROGEN-CONTAINING REACTANT {1} | |
423 | DF | .~.~> Reactant contains nitrogen as a ring member of a heterocyclic ring {1} |