I learned it from word of mouth from elders in Spain. Particularly from Vicens Ferrer from http://www.vferrer.net http://www.vferrer.net. You may ask him for bi

I learned it from word of mouth from elders in Spain. Particularly from Vicens Ferrer from http://www.vferrer.net http://www.vferrer.net. You may ask him for bibliographic references, if he knows of any.