Pustynnikova, E. V., I. S. Pinkovetskaia, and E. O. Uskova. “Influence of Cluster Integration on Innovation Activity: Evidence of Russian Regions”. Amazonia Investiga, vol. 7, no. 15, Aug. 2018, pp. 222-33, https://amazoniainvestiga.info/index.php/amazonia/article/view/452.