https://www.nber.org/papers/w17842
Authors. Criscuolo, C., Martin, R., Overman, H. & Van Reenen, J
Venue. NBER Working Paper 17842
How the Institute flags it
frontier 1 time established 1 time
This source carries more than one flag across the corpus. That is not an inconsistency to resolve: the same work can be established evidence for one claim and frontier evidence for another, and the flag belongs to the use rather than to the source.