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Die Materialwirtschaft im deutschen Steinkohlenbergbau
Lehmann, Hans-Joachim, (1968)
The Effect of Capital Intensity on the Optimal Rate of Extraction of a Mineral Deposit: A Comment.
Crabbe, Philippe J., (1982)
The contribution of L. C. Gray to the economic theory of exhaustible natural resources and its roots in the history of economic thought
Crabbe, Philippe J., (1983)
Gray and Hotelling: A reply
Crabbe, Philippe J., (1986)