Subclass Subgroup Patent
C03B 33/0235 09809483
  33/14 09809484
  35/24 09809485
C03C 3/093 09809486
    09809487
  10/0027 09809488
  17/10 09809489
  17/22 09809490
  17/32 09809491
  17/36 09809492
  19/00 09809493