books.google.com.echttp://books.google.com.ec/books/about/A_method_of_solution_of_the_critical_mas.html?id=bFap5xfM9e8C&utm_source=gb-gplus-shareA method of solution of the critical mass problem for a thermal pile with slowing down properties independent of position
A method of solution of the critical mass problem for a thermal pile with slowing down properties independent of position