A Expert on Prasthanatrayi the three sources is called Jagad Guru

https://en.wikipedia.org/wiki/Prasthanatrayi

https://www.youtube.com/results?search_query=Prasthanatrayi 

https://www.slideshare.net/search/slideshow?searchfrom=header&q=Prasthanatrayi 

Upanishads(Upadesha prasthana (injunctive texts), and Śruti prasthāna (starting point of revelation))

http://freeglobaluniversity.blogspot.com/search/label/Upanishad

The Brahma Sutras, known as Nyaya prasthana or Yukti prasthana (logical text or axiom of logic)

http://vedantaupanishad.blogspot.com/search/label/Sutras

Gita, is Sadhana prasthana (practical text), and Smriti prasthāna (start point of remembered tradition)

http://freeglobaluniversity.blogspot.com/search/label/Gitas 

All the founders of major schools of Vedanta, wrote bhāṣyas (commentaries) on above texts.

http://01sc.blogspot.com/search/label/Jagadguru