SISTEMA LEGAL DE UNIDADES DE MEDIDA DEL PERU LEY N ° 23560 https://www.inacal.gob.pe/repositorioaps/data/1/1/5/jer/mlegal/files/Ley-23560.pdf
https://www.cem.es/sites/default/files/siu8edes.pdf
https://www.bipm.org/en/si-brochure-9
https://www.bipm.org/en/publications/si-brochure
https://www.iso.org/iso-8601-date-and-time-format.html
https://www.gob.pe/institucion/inacal/campañas/7259-hora-oficial-del-peru-inacal