Richard Moss's dissertation "Slavery on Long Island" (published by
Garland under same title in 1993) includes Brooklyn (part of geographical LI).
See also Vivienne Kruger's dissertation, "Born to Run: The Slave Family in
Early New York, 1626-1827" Columbia University, 1985, 2 vols.  Both titles
appear on a "Bibliography of Dissertations and Theses on Long Island History"
that Hofstra University's Long Island Studies Institute will be publishing in
the fall.  There are some references also in Lynda R. Day's, "Making a Way to
Freedom: A History of African Americans on Long Island (Interlaken, NY: Empire
State Books/LI Studies Institute, 1997).
                Natalie Naylor, LI Studies Institute