Corrections

In the article by Yu. D. Shmyglevsky, “A Variational Problem in the Gas Dynamics of Axisymmetric Supersonic Flows,” published in DAN, vol. 113, no. 3, 1957, the equation on p. 522, line 7 from the bottom, should read

\[ \frac{dr}{d\psi} = -\frac{\omega'(a)\varphi(\psi)}{\sqrt{xr}}\, \sin(\vartheta-\alpha). \]

In the article by F. S. Klebanov, “On the Motion of Air through Mine Workings in the Presence of Worked-Out Spaces,” published in DAN, vol. 113, no. 4, 1957, formula (7) on p. 768 should read

\[ 2\int_{0}^{\beta x}\frac{dx}{\sqrt[n]{r(x)}} = \int_{0}^{x}\frac{dx}{\sqrt[n]{r(x)}}. \tag{7} \]

Formula (8) should read

\[ Q(x) = Q_{0} + \frac{Q_{0}^{2}m}{l r_{0} a} \left( \frac{R}{a} \ln \frac{2}{1+e^{-\alpha x}} + R_{2}l \right) (1-e^{-kx}). \tag{8} \]