Talk:Hartwick's rule

Formula
$$\dot{K}=\sum_i(p_i-MC_i)$$, where MC is marginal extraction cost, p is selling price and dK/dt is change in capital. Found in "Perman: Natural Ressource and Environmental Economics, 2003, p.90 (formula is not written explicitly but explained in text)" What do you think about that? --Saippuakauppias ⇄ 19:07, 1 November 2009 (UTC)