I'm no expert, but I think that's only in reference to the tribes inthe USA....for instance I noticed tribes from further north are not mentioned (like the Manitoo, etc...).

From what little my friends taught me, they have a fascinating history and culture....I sincerely hope it never fades away like it has been until it disappears  

Stay safe.

Perfection does not exist. The question therefore, is: what level of imperfection are we willing to settle for?