A modified oestrogen receptor ligand-binding domain as an improved switch for the regulation of heterologous proteins Littlewood, T.D.; Hancock, D.C.; Danielian, P.S.; Parker, M.G.; Evan, G.I. Nucleic Acids Research 23(10): 1686-1690 1995 https://eurekamag.com/research/008/047/008047674.php