TY  - BOOK
AU  - Williams, Howel.
TI  - Petrography: an introduction to the study of rocks in thin section / 
SN  - 0-7167-1376-4
U1  - H2 
PY  - 1977///
CY  - San Francisco : 
PB  - W.H.Freeman And Company , 
KW  - Igneous Rocks
ER  -