People v. Thomas , 62 Ill. 2d 375 ( 1975 )
Aguilar v. Texas , 84 S. Ct. 1509 ( 1964 )
Spinelli v. United States , 89 S. Ct. 584 ( 1969 )
United States v. Harris , 91 S. Ct. 2075 ( 1971 )