1. C. Fragassa, Int. J. Qual. Res. 9, 279–298 (2015).
2. A. Valchev, T. Ignatova, I. Grigorova, and I. Nishkov, in Proc. XXVII Int. Miner. Process. Congr. Santiago, Chile, edited by J. Yianatos, A. Doll, C. Gomez, and R. Kyvenhoven (IMPC Organisation, Santiago, 2014), pp. 244–256.
3. A new porcelainised stoneware material based on anorthite
4. Characterisation of some Clays Used for Whiteware Ceramics, II. Technological Characterization
5. M. Marinov, A. Valchev, I. Nishkov, and I. Grigorova, in Proc. 2nd Int. Symp. Process. Ind. Miner. (2010).