MALEKNIA, LALEH, et al. “Study on Morphology, Thermal and Physical Properties of Poly(trimethylene Terephthalate)-Nano Silica Composite”. Asian Journal of Chemistry, vol. 21, no. 9, Mar. 2010, pp. 6767-73, https://asianpubs.org/index.php/ajchem/article/view/12147.