I should recommend visiting the library of the Siam Society in Bangkok.
The Thai librarians will help you find monographs in English by scholars
~which may help you in your research of beads from Burma and Thailand.

S.E. Asia is one of the most seductive places in the world for bead collectors.
I admire your opportunity to see and buy some of the most desirable
antique beads becoming available in the market place today.

Have fun, Frederick II