Reference
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- 1965 . U.S. Department of Commerce, Office of Business Economics . Business Statistic ,
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- Wilson , W. H. 1941 . Occupational Deafness , M. S. Thesis University of Minnesota .
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- 1964 . “ Guide for Conservation of Hearing in Noise ” . In American Academy of Ophthalmology and Otolaryngology , 327 Los Angeles, California : South Alvarado Street .