“…[198,237] (optical spectra), [303,111] (emission line profiles and radial velocity measurements) [233] (optical and IR photometry), [142,315] (IRAS observations), [280,279,278,112,117] (radio emission), [116,274] (searches for maser emission), [187] (IUE observations), [35,238] (X-ray emission), [312] (symbiotic miras), [235] (symbiotic novae), [236,215] (extragalactic symbiotics) and in-depth investigations, e.g. [109,205,110,287,83] for AX Per alone.…”