  An expression for the coefficients of a linear iterative equation in terms of
the parameters of the source equation is given both for equations in standard
form and for equations in reduced normal form. The operator generating an
iterative equation of a general order in reduced normal form is also obtained
and some other properties of iterative equations are established. In
particular, a simple necessary and sufficient condition for an equation to be
iterative is given for the general fourth-order linear equation solely in terms
of its coefficients.
