1 Subjects: “...Self Administration...”

2 Subjects: “...Self Administration...”

3 Subjects: “...Self-administration...”

4 Subjects: “...Self Administration...”

5 Subjects: “...Self Administration...”

6 Subjects: “...Self-administration...”

7 Subjects: “...self-administration...”

8 Subjects: “...self-administration...”

9 Subjects: “...cocaine self-administration...”

10 Subjects: “...self-administration...”

11 Subjects: “...self-administration...”