BERKA-John F., 97. Visitation 4 p.m., wake service 7 p.m. June 18 at Vinton Street Chapel. Funeral Mass 10 a.m. June 19 at Immaculate Conception Church. Interment Calvary Cemetery. Preceded in death by wife, Catherine. Survived by sons, Robert Berka, Olathe, Kan., and Leonard Berka, Nixa, Mo.; eight grandchildren; 17 great-grandchildren; sisters, Rose Dworak and Ann Berka.