Two Batak pedang sabre

[Pendita65]

Picked up today two sabre of the Batak and according to the auction house they where from 19th or early 20th century, Borneo, Indonesia.
I used the pictures from the auction house as i didn't have the good light to take some images tonight.

1. Are these sabre from the Karo Tribe of Sumatra? or did the Karo also lived
in Borneo?
2. the sabre are also seen in the drawing from the Book by Wilhelm Volz band
Nord Sumatra
3. Would like to read more about these weapons any recomendation for
suitablte publications?

regards, Martin