共 13 条
[1]
[Anonymous], 1939, [No title captured], Patent No. [2152852, US2152852A]
[2]
GRESHAM WF, 1952, Patent No. 2607805
[3]
Larson AT, 1939, US Patent, Patent No. [2,153,064, 2153064]
[4]
LODER DJ, 1942, Patent No. 2285448
[5]
NIELSEN DR, 1979, Patent No. 4141930

