The compounds of the following formula:wherein R, R2, R3 and A have the meanings given in the specification, are endowed with selective A3 adenosine receptor antagonist activity. In a preferred embodiment, the inventive system of interconnected ornamental rings comprises a pair of separate finger rings, each having a connection point at which there is attached a decorative chain interconnecting the separate rings. The present invention also provides a method for screening the eligibility of a subject for OGF modulation or treatment by assessing the level of OGF receptor and the relevant CKI. Another process involves displaying the clusters of items to the user via a collection management interface that enables the user to attach cluster-level metadata, such as by rating or tagging entire clusters of items.