Koleva, E., I. Kolev, and I. Balabanova. “Simulation of Optoelectronic Analog Circuits With PSPICE Package”. Elektronika ir Elektrotechnika 96, no. 8 (October 20, 2009): 99-102. Accessed September 21, 2020. https://eejournal.ktu.lt/index.php/elt/article/view/9962.