//-->
A wolfram in sheep's clothing : economic warfare in Spain and Portugal, 1940 - 1944
Caruana, Leonard, (2000)
Technological alternatives for the conservation of strategic and critical minerals, cobalt, chromium, manganese, and platinum-group metals : a review
Foster, Russell J., (1985)
Cobalt
Kirk, William S., (1985)
Sibley, Scott F., (1979)
Nickel
Sibley, Scott F., (1985)