In this article, the author argues that the method of comparison of techniques adopted by Sraffa can be extended beyond the area of constant returns to scale or diminishing returns on land. The case of variable returns at the industry level related to external diseconomies is investigated. It is...

This paper proposes a revised theory of the classical notion of normal prices for an economy with exhaustible natural resources. The author introduces the notion of effectual supply and argues that Sraffa's equations, without the Hotelling rule equation, can be reformulated to deal with the...