Referencing composite Primary KEYS

Hi,
i want to make a reference from a table on itself.
The table has a composite Primary Key. But I just want to refernce the TEstCaseID.
So whats wrong? Can anyone help me?

CREATE TABLE dbo.TestCase (
Project_projectID VARCHAR(20) NOT NULL references Project,
testCaseID VARCHAR(50) NOT NULL,
PRIMARY KEY(Project_projectID, testCaseID),
FatherID VARCHAR(50) references TestCase(testCaseID)

)

THanx CreanFor logical reasons, you can only reference unique values. Otherwise, how would SQL Server (or any database engine) know which of many records you were referencing?|||:D Already found out. But thanx a lot