Study of gallstones by spectroscopic methods / A. A. Pichugina, L. V. Tsyro, D. A. Afanasyev [et.al.] // Journal of applied spectroscopy. 2017. Vol. 84, № 1. P. 87-91. URL: http://vital.lib.tsu.ru/vital/access/manager/Repository/vtls:000582065