“…Note that the main issue about V-O fractional functional equations is difficulty in obtaining their exact solutions. In recent years, many approximate methods have been applied to solve such problems; for instance, see Heydari et al (2019a, 2019b), Bhrawy and Zaky (2017, 2016), Hafez and Zaky (2019), Parsa Moghaddam and Tenreiro Machado (2017), Keshi et al (2018), Hosseininia and Heydari (2019a, 2019b), Hassani et al (2019a, 2019b) and Hassani and Naraghirad (2019).…”