Agrawal, M., Pich, A., Gupta, S., Zafeiropoulos, N. E., Simon, P., & Stamm, M. (2008). Synthesis of Novel Tantalum Oxide Sub-micrometer Hollow Spheres with Tailored Shell Thickness. Langmuir, 24, 1013-1018. doi:10.1021/la702509j.