We have published the following mahjong-related literature.
A Riichi Mahjong Study Book (without a clever name)
Written by Jenn Barr and Garthe Nelson, this is the next step for budding mahjong players. This is recommended for young intermediate players. The book has a small section of drills typical in Japanese mahjong teaching, and then moves on to real situations analyzed and discussed by Jenn and Garthe.
This publication is available as an e-book and a hard copy.
Available from these sellers:
Nanimonoda Show is a live-streaming chat show run on the niconico site, starring Jenn Barr (Yasha Jenn), Garthe Nelson (Bagaasu), Gemma Collinge (Erai Gemma). It is solely in Japanese.
The Nanimonoda Team run a blog and are also available for live shows and appearances. For more information please see the following sites:
[Nanimonoda page] In Japanese only.
[Nanimonoda blog] In Japanese only