Wikipedia for about 40 references.
Introduced into the US military in 1965 to replace the M51 which replaced the M43 (you can figure the years).
The exterior is poly cotton mix, there is a 100% cotton lining and a further, buttoned on detachable inner warm layer. The instructions warn not to dry it on a stove, so I guess that was a problem.
What's amazing is that in 1965 they correctly predicted the dimensions of the now popular seven inch tablets and a Nexus 7 fits nicely in the side pockets. Great forethought there. Available at army disposals stores globally.