Pisula, W., J. Pigłowski, and C. Kummerlöwe. “Preparation and Characterization of Copolyesters of poly(tetramethylene Succinate) and poly(butylene Terephthalate)”. Polimery, vol. 51, no. 5, Aug. 2022, pp. 341-50, https://ichp.vot.pl/index.php/p/article/view/1531.