literature review
https://drive.google.com/drive/folders/1HHPFOz6jkRlNiRUyj4m4HDKt5wABJWKp?usp=sharing
https://drive.google.com/drive/folders/1WuzCUfNA5d2AjUZELKH_GzNvuixOzzOM?usp=sharing
འབྲེལ་ལམ་https://drive.google.com/drive/folders/1HHPFOz6jkRlNiRUyj4m4HDKt5wABJWKp?usp=sharing་ཨེབ་གཏང་སྟེ་ རྒྱབ་རྟེན་ཁ་ཕྱེ་