Wang HJ, Cao Y, Cao C, Sun YY, Yu XH, Zhu LF, Yang L. Parinaric acid methyl ester polymer films with hill-structured features: fabrication and different sensitivities to normal and tumor cells. ACS Appl Mater Interfaces. 2011 Jul;3(7):2755–63. doi: 10.1021/am200544c. PMID: 21682341.