  In many government applications we often find that information about
entities, such as persons, are available in disparate data sources such as
passports, driving licences, bank accounts, and income tax records. Similar
scenarios are commonplace in large enterprises having multiple customer,
supplier, or partner databases. Each data source maintains different aspects of
an entity, and resolving entities based on these attributes is a well-studied
problem. However, in many cases documents in one source reference those in
others; e.g., a person may provide his driving-licence number while applying
for a passport, or vice-versa. These links define relationships between
documents of the same entity (as opposed to inter-entity relationships, which
are also often used for resolution). In this paper we describe an algorithm to
cluster documents that are highly likely to belong to the same entity by
exploiting inter-document references in addition to attribute similarity. Our
technique uses a combination of iterative graph-traversal, locality-sensitive
hashing, iterative match-merge, and graph-clustering to discover unique
entities based on a document corpus. A unique feature of our technique is that
new sets of documents can be added incrementally while having to re-resolve
only a small subset of a previously resolved entity-document collection. We
present performance and quality results on two data-sets: a real-world database
of companies and a large synthetically generated `population' database. We also
demonstrate benefit of using inter-document references for clustering in the
form of enhanced recall of documents for resolution.
