advanced macroeconomics ,second  edition ,david romer,上海财经大学出版社，p26。，第二段，最后一句，if output per worker differs by afactor of X,the difference in log output per worker between the two economics is lnX.since the elasticity of output per worker with respect to capital per worker is Ak,log capital per worker must differ by(lnX)/Ak,that is , capital per worker differs by a factor of exp{(lnX)/Ak},or ...