c1 Refereed Journal Article. MA 22/7/14. 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 cannot archive publisher's version/PDF 
Requested (Peng) accepted v.& Permission, 19.8.14-MMM