The Cache Control header and {HEAD ~ its operation} are explained in {TAIL ~ paragraphs} 12.8 and 13 of the RFC 2326 
explained in
The Cache Control header and { HEAD ~ its operation } are explained in { TAIL ~ paragraphs } 12.8 and 13 of the RFC 2326
OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD OTH REL REL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH