
References:
Others
- National Institute of Standards and Technology (https://www.nist.gov/pml/weights-and-measures/metric-si/si-units)
- Discover Magazine (https://www.discovermagazine.com/the-sciences/why-1-second-is-1-second)
- How Stuff Works (https://science.howstuffworks.com/avogadros-number.htm)