| 359 / | HD | OPTICS: SYSTEMS (INCLUDING COMMUNICATION) AND ELEMENTS |
| 838 | DF | MIRROR {14} |
| 850 | DF | .~ Plural mirrors or reflecting surfaces {7} |
| 857 | DF | .~.~ With successive reflections {4} |
| 858 | ![]() | .~.~.~ Including curved mirror surfaces in series {1} |
| 859 | DF | .~.~.~.~> With concave and convex mirrors in series |