León Bermúdez, Adan Yovani, and Ramiro Salazar. 2008. “Synthesis and Characterization of the Polystyrene - Asphaltene Graft Copolymer by FT-IR Spectroscopy”. CT&F - Ciencia, Tecnología Y Futuro 3 (4):157-67. https://doi.org/10.29047/01225383.469.