LL 13.4.16.
Green in Sherpa: Author's Pre-print: author can archive pre-print (ie pre-refereeing)
Author's Post-print: 	author can archive post-print (ie final draft post-refereeing)
Publisher's Version/PDF: author can archive publisher's version/PDF
General Conditions: Published source must be acknowledged
    Publisher's version/PDF may be used
    Authors retain copyright
    Creative Commons Attribution License. --
29.4.16--MMM.
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CC-BY-4.0 added LL 14/6/19