TY  - JOUR 
T1  - Stoichiometry-based estimates of ferric iron in calcic, sodic-calcic and sodic amphiboles: a comparison of various methods
JO  - Anais da Academia Brasileira de Ciências
A1  - Gualda, Guilherme A.R.
A1  - Vlach, Silvio R.F.
SN  - 0001-3765
UL  - 10.1590/S0001-37652005000300012
VL  - 77 
Y1  - 2005
PB  - Brazil 
ER  -