this article from a while back provides a nice summary of current thinking (there's a bunch of waffle at the top of the aritcle before getting into the guts of

this article from a while back provides a nice summary of current thinking (there's a bunch of waffle at the top of the aritcle before getting into the guts of it about midway through ) https://www.stuff.co.nz/travel/destinations/asia/67390585/null https://www.stuff.co.nz/travel/destinations/asia/67390585/nu...