  Killing-Yano (KY) two and three forms of a class of spherically symmetric
space-times that includes the well-known Minkowski, Schwarzschild,
Reissner-Nordstrom, Robertson-Walker and six different forms of de Sitter
space-times as special cases are derived in a unified and exhaustive manner. It
is directly proved that while the Schwarzschild and Reissner-Nordstrom
space-times do not accept any KY 3-form and they accept only one 2-form, the
Robertson-Walker space-time admits four KY 2-forms and only one KY 3-form.
Maximal number of KY-forms are obtained for Minkowski and all known forms of de
Sitter space-times. Complete lists comprising explicit expressions of KY-forms
are given.
