1. General Electric, Japan Kokai 75-131908, 75-151864, 76-76263, 76-76264.
2. Mitsubishi Chemical Industries, Japan Kokai 74-49910, 75-62916,75-64203, 76-29426, 77-19610, 77-19611.
3. Toyo Soda Manufacturing, Japan 73-27290.
4. Sumitomo Chemical Industries, Japan Kokai 77-91817, 78-2414, 78-84913, 79-14914.