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This free course was written by Martin Pennington.
Except for third party materials and otherwise stated (see terms and conditions [Tip: hold Ctrl and click a link to open it in a new tab. (Hide tip)] ), this content is made available under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 Licence.
The material acknowledged below is Proprietary and used under licence (not subject to Creative Commons Licence). Grateful acknowledgement is made to the following sources for permission to reproduce material in this free course:
Figure 1: © AnsonLu/iStockphoto.com
Figure 2: Green Office Engro in Flickr made available under Creative Commons Attribution 2.0 Licence.
Figure 3: Commencement 2008 228 in Flickr made available under Creative Commons Attribution 2.0 Licence.
Figure 4: The grindstone in Flickr made available under Creative Commons Attribution 2.0 Licence.
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