You can see plane list of all works including publishers.
You can buy scores through URLs below:

Above URLs have only Japanese pages.

When you want to order scores in English, you can buy them through YUI Shuppan.
Also concerning pieces which don't published above publishers, you can order scores to YUI Shuppan.
YUI Shuppan will supply you copies from original scores etc.
E-mail address of YUI Shuppan: yui@ori.bbiq.jp