I am searching for any scientific literature about 'SPARQL aggregation query rewriting against virtual views'. To clarify the terms used:

aggregation SPARQL query usually takes the form of SELECT RD WHERE GP GROUP BY GRP, where RD is the result description based on a subset of variables in the graph pattern GP. GP defines a BGP and optionally uses functions, such as assignment (e.g., BIND) and constraints (e.g., FILTER). GRP defines a set of grouping variables, whereas RD contains selection description variables as well as aggregation variables with corresponding aggregate functions. 

A virtual view is a non-materialized views, that is basically defined as a SPARQL query.

The current state of the art - according to my attempted search on Google scholar- defines either one of:

1. Normal (non-aggregative) SPARQL query rewriting.

2. Aggregate SPARQL query rewriting using materialized views.

3. SQL aggregate query rewriting.

All of those three don't match my need.

Anyone knows some resource related to what I need?