What is the test for constructive possession of a drug dealer?

In the cases in which we have upheld narcotics convictions on the basis of constructive possession, the defendant's dominion over the contraband was established by clear evidence of his dominion over the residence or vehicle in which the contraband was found. See, e.g., United States v. Soyland, 3 F.3d 1312, 1315 (9th Cir.1993) (constructive possession found where drugs and large sum of cash discovered in defendant's car and circumstances of defendant's prior arrests mirrored those of instant offense); United States v. Walker, 993 F.2d 196, 200 (9th Cir.), cert. denied, --- U.S. ----, 114 S.Ct. 276, 126 L.Ed.2d 227 (1993) (constructive possession found where defendant possessed keys to the inner and outer doors to the apartment and the three bedrooms where the drugs were found and defendant's clothes and shoes, a receipt bearing his name and a large sum of cash found near the drugs in one bedroom).