"2.2 Nitrogen oxide (NOx)". 2. Measuring instruments for stationary source, Air Pollution Continuous Monitoring Technology in Japan. Global Environment Centre Foundation. Archived from the original on 2017-09-16. Retrieved 2020-01-16.
"2.2 Nitrogen oxide (NOx)". 2. Measuring instruments for stationary source, Air Pollution Continuous Monitoring Technology in Japan. Global Environment Centre Foundation. Archived from the original on 2017-09-16. Retrieved 2020-01-16.