Azocalix[4]arene with three distal ethyl ester residues as a highly selective chromogenic sensor for Ca<sup>2+</sup> ions.Published in:Heterocyclic Communications, 2018, v. 24, n. 3, p. 147, doi. 10.1515/hc-2017-0239By:Wang, Jie;Guan, Hongyu;Ge, Chunhua;Fan, Ping;Xing, Xijuan;Shang, YunshanPublication type:Article