The Article "ISO 14001 Monitoring & measurement equipment control" refers to "clause 4.5.1 of ISO 14001". But in the latest version (2015) there is no such clause. (?)
What does that mean? Are there no more procedures to monitor and measure key characteristics necessary?
The article is written based on old version of the standard. The requirements for monitoring and measuring equipment in 2015 version of the standard are located in clause 9.1.1. The only requirement regarding monitoring and measuring equipment is for organizations to ensure that calibrated or verified monitoring and measurement equipment is used and maintained, as appropriate.
Monitoring and measuring of environmental performance is still necessary, but there is no requirement for documented procedure. Requirements for monitoring and measuring environmental performance are located in clause 9.1.1
You should update the referred clauses.
Especially because you explicitly refer to ISO 14.001: 2015 in "ISO 14001 Documentation Toolkit" as well as in "Checklist of Mandatory Documentation Required by" (White paper).
Otherwise it is confusing and impeding working with the checklist or toolkit.