a quick first try might be usa.gov. The search "Tompkins Square Park" and labor and history gets 2 hits. The first one, Landmarks Preservation Commission June 20, 2006, Designation List 377 says on page 12: "As early as 1874, a “rally of unemployed workers was broken up with some violence by the police.”74 This early “Tompkins Square Massacre” presaged the more recent confrontation that took place in August 1988 and became known as “The Battle of Tompkins Square"
The reference number 74 is Malve Von Hassell, Homesteading in New York City, 1978-1993. The Divided Heart of Loisaida (Westport, CT: Bergin & Garvey, 1996), pp.43-44
You may be safer going with the broader search: "Tompkins Square Park" history (10 hits), or even "Tompkins Square Park" (about 42 hits), to be sure you don't miss something relevant that uses slightly different words. One of my rules is "the more words you use, the bigger chance one of them will be the wrong one", so I try to pick out just 2 or 3 words in unusual combinations that pin down what I am looking for without producing thousands of hits.
There is also scholarly research on Tompkins Square Park. Dissertation Abstracts (available on site at academic libraries, or via remote student/staff ID) gets 1 hit for the search tompkins square park: “Parallel universes: Anarchy and ethnicity. A study of politics, real estate and ritual in the East Village, NYC” by Tiefenbacher, Lyn, Ph.D., Temple University, 1995, 387 pages; proquest.umi.com order number AAT 9527541. Possibly you could get this dissertation on interlibrary loan – to check its bibliography for more leads. America: History and Life gets 2 hits for the keyword search: tompkins square park. JSTOR (all full text online) gets 34 hits for "tompkins square park", and this might be a good source to try first. Academic Search Premier, gets 34 hits for tompkins square park, but only 9 if you limit to full text. If you need to use public libraries, many will have the more “general interest” Masterfile Premier, which gets 69 hits (10 full text) for tompkins square park. Many other databases would help with this – SocIndex gets 2 hits for tompkins square park, Sociological Abstracts gets 6 hits, and Project Muse (another full-text scholarly database), gets 7 hits for “tompkins square park” (must use quotes in that one).
