4MEULEMAN M. WOUTER DE MAESENEIRE. Do R&D subsi- dies affect SMEs'aecess to external financing? [ J]. Res Policy, 2012,41 (3) :580 -591.
5COLOMBO MG, CROCE A, GUERINI M. The effect of public subsidies on firm'investment-cash flow sensitivity: Transientor persistent? [ J ]. Res Policy,2013,42 (9) : 1605 - 1623.