1. Merck Research LaboratoriesBlue BellPAUSA
2. Merck Research LaboratoriesWest PointPAUSA
3. Merck Research LaboratoriesRahwayNJUSA
4. Merck Research LaboratoriesTerlings ParkUnited Kingdom
5. Vanderbilt UniversityNashvilleTNUSA
6. California Clinical TrialsGlendaleCAUSA