1. Preparation and Properties of Carbon Foam
2. C. R. Schmitt, U. S. Pat. 3, 264, 073, 1966.
3. Gen. Technologies Corp., Belg. Pat. 743, 442, 1969.
4. The formation of hollow spheres by the pyrolysis of resin fractions extracted from coal tar pitches
5. Soc. Aerosp. Mater. Process Eng., 16th Natl. Symp.;Amagi,1971