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https://www.nist.gov/video/por-que-las-mascarillas-con-valvulas-no-reducen-la-propagacion-de-covid-19-2-de-2

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# Por qué las mascarillas con válvulas no reducen la propagación de COVID-19 (2 de 2)

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## Appears In

                        - Por qué las máscaras con válvulas no disminuyen la propagación de COVID-19 (2 of 2): Una transcripción del video (incluyendo una descripción de las imágenes)

November 8, 2020

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