Duy Thien, Nguyen, 		Tu, Nguyen, 		Hoa, Nguyen, 		Doanh, Sai, AND 		Vu, Le.
" Fabrication, Characterization of SiO2 Nanospheres  and SiO2 Opal Photonic Crystals" <em>VNU Journal of Science: Mathematics - Physics</em> [Online], Volume 37 Number 1 (12 March 2021)