\BOOKMARK [1][-]{section.1}{Introduction}{}% 1
\BOOKMARK [1][-]{section.2}{Alternative form of ``Katriel's proof''}{}% 2
\BOOKMARK [1][-]{section.3}{A generalization of Spivey's Bell number formula}{}% 3
\BOOKMARK [1][-]{section.4}{Remarks}{}% 4
\BOOKMARK [1][-]{section.5}{Acknowledgment}{}% 5