"I am interested in the name of Greenberg or Gruenberg from Kritzow which is in Mecklemberg. Carl immigrated in 1863 to Milwaukee"
There are entries for Greenberg Gruenberg Grünberg in "Milwaukee's German Newspapers; an index of death notices and related items" (1844-1950). These include entries for a Charles Grünberg who received letters postmarked from "Neubeckow", which were held at the Milwaukee post office, and a Carl Gruenberg who died in 1895.
Gary Rebholz, compiler/editor
Indexing Milwaukee's German newspapers continuously since 2007... helping family researchers find their ancestors among Milwaukee's 99%.