SLS 546 : 1981 : Specification for general writing Lead pencils .
- Colombo BCS 1981
- 11p.
STD2740
SLS 546 : 1981
a686.863.3
SRI LANKA-STANDARDS
STANDARDS-SRI LANKA
686.863.3
STD2740
SLS 546 : 1981
a686.863.3
SRI LANKA-STANDARDS
STANDARDS-SRI LANKA
686.863.3