TITLE: References on semismall maps
QUESTION [6 upvotes]: Where can I find references on semismall maps, in the sense of Goresky and MacPherson? I don't want to restrict to the case where the base is $\mathbb C$ (an arbitrary alg. closed field would be fine), or maps $f:X\to Y$ from a smooth variety $X.$ In particular, I'd like to find the proof (if the statement is correct, which I'm not sure) that $Rf_*$ takes an irreducible (middle) perverse sheaf $F$ supported on $X$ to a perverse sheaf; I can only do this when $X$ is smooth and $F$ is a lisse sheaf, or when all the fibers of $f$ have dimension at most one. 
Recall: A proper surjective morphism $f:X\to Y$ is called $semismall$ if $\dim X\times_YX=\dim X.$
Thank you.

REPLY [6 votes]: The statement that $Rf_*$ takes a middle perverse sheaf to a perverse sheaf is not true for arbitrary perverse sheaves:
For example, let $Y$ be a smooth surface and $X$ the blow up of $Y$ at a point. Let $E$ be the exceptional divisor and $F$ the constant sheaf on $E$ placed in degree $-1$ (to make it perverse). The natural morphism $f:X \to Y$ is small but $Rf_* F$ is not perverse since it has cohomology sheaves supported on a point in degrees $-1$ and $1$.
EDIT: The other counterexample, suggested in a previous edit, does not appear to work.