This is a decade old and is directed at rubble foundations, but contains interesting matter.
http://www.buildingscience.com/documents/insights/bsi-045-double-rubble-toil-trouble/?searchterm=frost%20protected%20shallow (http://www.buildingscience.com/documents/insights/bsi-045-double-rubble-toil-trouble/?searchterm=frost%20protected%20shallow)
Thanks for the link. Interesting read.
Alan