1. The Measurement of Stress in Rocks;Leeman;Jl. S. Afr. Inst. Min. Metall.,1964
2. Measuring Stresses and Deformation in Solid Materials;Hast;Diss. Roy. Inst. Tech. (KTH),1943
3. On the Measurement of Stresses in Solids;Hult;Chalmers Tekniska Högskolas Handlingar Nr. 280,1963