Veena

http://www.rudraveena.org/
http://www.rudravina.com/
https://www.youtube.com/results?search_query=Rudra+veena

http://kailashamarnath.blogspot.com/search/label/Ravanahatha
https://www.slideshare.net/search/slideshow?searchfrom=header&q=Rudra+veena

jabala Upanishad

https://en.wikipedia.org/wiki/Rudrakshajabala_Upanishad
https://www.youtube.com/results?search_query=Rudraksha+Jabala+Upanishad