TY  - BOOK
AU  - Helvich, Kenneth.
ED  - Association of Official Analytical Chemists
TI  - Official methods of analysis
U1  - 630.24 
PY  - 1990///
CY  - Arlington, Vir.
PB  - The Association
KW  - QuÃ­mica agrÃ­cola
KW  - QuÃ­mica analÃ­tica
N1  - 39-65
ER  -