what (if anything) have you used for pedagogical materials for the guqin? and how effective have they been?

i'd like to futz around with an instrument in that family someday, but there aren't lessons available anywhere near me.

i take lesson once a week from a teacher and the primary focus is technique and learning pieces. I'm also in a facebook group where there are some music scholars who like to study the history, culture and systems related to this instrument. After ~8 months of learning I feel more comfortable with the basic techniques now so I've ventured into reconstructing ancient scores and the group has been helpful in helping me understanding certain notations.