Aparelho auditivo de carbono Acousticon A
1905
1905
1908
1909
1910
1910
1925
1925
1927
1927
1927
1930
1930
1930
1930
1930
1930
1932
1932
1932
1932
1933
1934
1934
1935
1935
1935
1937
1937
1938
1941
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