I'll try and find it but with approx 120 links in my RSd favourites folder and 364 articles papers and letters in my RSD documents folder it could take sometime, if I remeber correctly it came from Howard. http://www.thblack.com/links/RSD/index.html
meantime here is one artocle on SCS's

http://www.rsdinfo.org/CRPS-SCS%20Article.pdf