noticed that it was from the Environmental Control Board of New York City and the guy gave me the fine did not mark any of those violations listed in the summons. Instead, he put down "56RCNVI-03-(a)(3)" followed by "Unauthorized presence in parks when closed".
I did not find the code he put down anywhere on the web and it is just too much effort to appeal, which they (city) know. The park cops without proper uniforms in 1980's jeep must be as hungry as the wild cats.