Khemakongkanonth C, Netngamsawang C. The Competition in Voice Service Market between Network Operators and OTT Service Providers . JDC [Internet]. 2023 Jun. 19 [cited 2024 May 21];7(1):109-27. Available from: https://so04.tci-thaijo.org/index.php/NBTC_Journal/article/view/260756