Gaya APA
Ltd., R, I, S. (1979).
The Economics of Tantalum third Edition 1979 .
London:
Roskill Information Services, Ltd..
Gaya MLA
Ltd., Roskill, Information, Services.
"The Economics of Tantalum third Edition 1979".
London:
Roskill Information Services, Ltd.,
1979.
Text.