1. Tunnel boring technology—disk cutter experiments in sedimentary and metamorphic rocks;Morrell;U.S. Bur. Mines, RI 7410,1970
2. Studies on the cutting of rock by rotary cutters—Part I;Takaoka;Tunnels & Tunnelling,1973
3. Tunneling machine research—interaction between disk-cutter grooves in rocks;Rad;U.S. Bur. Mines. RI 7881,1974
4. A Geology for Engineers;Blyth,1974
5. A modification of sandstone classification;Chen;J. Sedim. Petrol.,1968