you project your ignorance on everyone here. The Lisbon agreement was signed on March 18th 1992. Zimmerman went to Sarajevo on the 28 March 1992---the same day that Izzie recinded his signature. March is the spring hopalong. Not the summer. Sleep well.
Further, Burg and Shoup covered the issue in some depth in "The War in Bosnia-Herzegovina: Ethnic Conflict and International Intervention". The only thing agreed to was a framework with which to solve Bosnia's interethnic issues, but the Serbs' transition to military force to settle the issue rendered continued negotiations moot.
In short, not only do you possess embarrassingly little information, but that which you do cling to so tenaciously is demonstrably wrong.
Work on that, m'kay?