Chandrasekhar, S.  "On algebraically special perturbations of black holes." In: Proceedings of the Royal Society, Series A, #1802, 8 March 1984, volume 392.  Article occupies pp 1-13 int he issue of 1-245pp.  Original wrappers, ex-library, with stamps on front and back wrappers.  Nice copy for this.  $50

"Algebraically special perturbations of black holes excite gravitational  waves that are either purely ingoing or purely outgoing. Solutions, appropriate to such perturbations of the Kerr, the Schwarzschild, and the Reissner-Nordstrom black-holes, are obtaine in explicit forms by different methods. The  different methods illustrate the remarkable inner relations among  different facets of the mathematical theory. In the context of the  Kerr black-hole they derive from the different ways in which the  explicit value of the Starobinsky constant emerges, and in the context of the Schwarzschild and the Reissner-Nordstrom black-holes  they derive from the potential barriers surrounding them belonging to a special class."--from the Royal Society site