共 17 条
[1]
BOESE, 1938, Patent No. 2108427
[3]
DICKEY JB, 1947, Patent No. 2432394
[6]
HAGEMEYER HJ, 1948, Patent No. 2450754
[7]
HASCHE RL, 1948, Patent No. 2453317
[9]
Hull D. C., 1947, US Pat, Patent No. [2 422 016, 2422016]