Priadilova, O., Cheng, W., Tommaseo, G., Steffen, W., Gutmann, J. S., & Fytas, G. (2005). Probing the micromechanical behavior of semicrystalline polypropylene films by Brillouin spectroscopy. Macromolecules, 38(6), 2321-2326. doi:10.1021/ma047747k.