For further reading please follow:
https://doi.org/10.2166/wcc.2018.271
http://www.was.org/magazine/Search.aspx
https://doi.org/10.14321/aehm.024.03.10
https://doi.org/10.2166/wcc.2020.194
https://doi.org/10.14321/aehm.024.04.11
Pen culture system