VALCHEVA, N. and IGNATOV, I. (2022) “MICROBIOLOGICAL EFFECTS OF COMBINATIONS OF COLLOIDAL SILVER (Ag), COPPER (Cu), SILICON (Si) AND ZINC (Zn) NANOPARTICLES FOR WASTE WATER”, UTTAR PRADESH JOURNAL OF ZOOLOGY, 43(11), pp. 45–50. doi: 10.56557/upjoz/2022/v43i113049.