
Muldivo 'Mentor' calculator model WSR, 160 c1955.
circa 1955
circa 1955
1957
1957
1956
1955
1955
circa 1955
1955
1955; 1830
1955
1955
1954-1955
1955
1955
1957
1957
1955
1956
1955
1954
1957
1955
1956
1956
1956
2000-100 BCE
1957
1957
1957
1957
1954
circa 1955
circa 1956
1955
1955
circa 1956
1839 (original); circa 1988 (replica)
1956
1950
1990-96
circa 1955
1955
1955
1955
1954
1955
1957
1954
1903 (original); 1982 (model)
1957