Contact the National Center for Non-profit Boards,  in Washington, DC.  They
publish a specialized series of pamphlets on myriad non-profit issues.  All of
those I have used were excellent.  They also produce general texts on the
subject.
Mary Case and I are both among museum people who have attended one or more of
their training programs as well. Startegic management is not a subject I take
to naturally, but I benefitted enormously.  No, this is not an ad for NCNB,
but I do want colleagues to know that its services have won me over through a
variety of experiences with them.