Grateful acknowledgement is made to the following sources:

Course banner image: momente/Shutterstock.com:
https://www.shutterstock.com/image-photo/industrial-pipe-valves-detail-179682341

Video background (Introduction video and Videos 3 and 7): Kekyalyaynen/Shutterstock.com:
https://www.shutterstock.com/image-photo/group-big-sedimentation-drainages-water-recycling-69608080

All other content is (c) Judd and Judd Ltd.