Cuong, B. C. “PYTHAGOREAN PICTURE FUZZY SETS(PPFS), PART 2- SOME MAIN PICTURE LOGIC OPERATORS ON PPFS AND SOME PICTURE INFERENCE PROCESSES IN PPF SYSTEMS”. Journal of Computer Science and Cybernetics, vol. 38, no. 1, Mar. 2022, p. 1-14, doi:10.15625/1813-9663/38/1/15992.