BibTex format
@unpublished{Martin:2016,
author = {Martin, R and Van, Reenen J and Elias, Einiö E and Nguyen, K-T and Dechezleprêtre, A},
title = {Do tax Incentives for Research Increase Firm Innovation? An RD Design for R&D},
url = {https://www.nber.org/papers/w22405},
year = {2016}
}