[1]
A. Marconi and I. O. Abrahão, “ Simetry of stereograms used in the determination of the optical indicatrix of minerals ”, An. Esc. Super. Agr. Luiz de Queiroz, vol. 33, pp. 407–413, Jan. 1976, doi: 10.1590/S0071-12761976000100037.