@article{zhang_li_wu_2011,  title={Zr(HSO4)4 as an efficient catalyst for the preparation of 10-aryl-6,8-dimethyl-6,10dihydro-5-oxa-6,8-diazaanthra[2,3-d][1,3]dioxole-7,9-diones under solvent-free conditions},  volume={22},  ISSN={0103-5053},  url={https://doi.org/10.1590/S0103-50532011000700006},  DOI={10.1590/S0103-50532011000700006},  number={7},  journal={Journal of the Brazilian Chemical Society},  publisher={Sociedade Brasileira de Química},  author={Zhang, Jiangli and Li, Wei Lin and Wu, Li Qiang},  year={2011},  month={Jul},  pages={1236–1240} }