Query question, OINV, OCRD, CRD1

When I try to create a query with the 3 tables above when I add the CRD1 the invoice numbers begin to duplicate. Is this a problem with the JOIN statements automatically created by the Generator?

Thanks, Jeff

SELECT *

FROM OINV T0 INNER JOIN OCRD T1 ON T0.CardCode = T1.CardCode

INNER JOIN CRD1 T2 ON T1.CardCode = T2.CardCode