Functional Equations and Tempered Ultradistributions Dušanka Perišić (1994) Publications de l'Institut Mathématique
Functional equations and tempered ultradistributions. Perišić, Dušanka (1994) Publications de l'Institut Mathématique. Nouvelle Série
Further extending results of some classes of complex difference and functional equations. Zhang, Jian-Jun, Liao, Liang-Wen (2010) Advances in Difference Equations [electronic only]