Preference of ophthalmic frames and their economic value in users aged 18 to 35 in the coop. Juan montalvo from the north sector of Guayaquil december 2022 – april 2023. JSR [Internet]. 2024 May 23 [cited 2026 Sep. 22];8(II CICS). Available from: https://revistas.utb.edu.ec/index.php/sr/article/view/3131