Ozoliņš, O., and Ģ. Ivanovs. “Realization of Optimal FBG Band–Pass Filters for High Speed HDWDM”. Elektronika Ir Elektrotechnika, vol. 92, no. 4, Apr. 2009, pp. 41-44, https://eejournal.ktu.lt/index.php/elt/article/view/10224.