1. Soden A L. A Practical Manual of Rubber Hardness Testing, Maclaren and Sons, 1951.
2. Kucherskii A M, Kaporovskii B M. Polym. Test., 16, 5, 1997, p481.
3. ISO 18517, 2015. Hardness testing - Introduction and guide.
4. ISO 48, 2010. Determination of Hardness (Hardness between 10 and 100 IRHD).
5. Hawley S. Polym.Test., 16, 4, 1997, p327.