Chu, P. T. B., H. T. T. Phan, H. D. Nguyen, and T. T. P. Phan. “Development of Inducer-Free Expression Plasmids Using IPTG-Inducible Pspac Promoter for Bacillus subtilis”. Vietnam Journal of Science, Technology and Engineering, vol. 63, no. 1, Mar. 2021, pp. 64-70, doi:10.31276/VJSTE.63(1).64-70.