We should be able to query by Entity Type (i.e. 'book', 'paper', etc.)
In the Evaluate API endpoint, we should be able to query based on Entity Type
i.e. the following API call:
should return results which are 'book's
David Rayner commented
I think you can achieve this using the (undocumented) Pt field.
From what I can gather you can query each type as follows:
Value Paper Type
1 Journal papers
3 Conference papers
for example, expr=And(Y=2016,Or(Pt='1',Pt='3')) will return journal and conference papers from 2016.