Raytchev T., Toncheva R., Donov D., Józefaciuk G., Sokołowska Z.:  Ion-excange ability of soil adsorbent, kinetics of cation desorption. (2005 r.) Institute of Agrophyscis PAS, Lublin, "Physicochemical character of soil adsorbent" 2005, 114-132 

Raytchev T., Donov D., Paskaleva K., Hubenov G., Sokołowska Z., Hajnos M.:  Impact of the analytical treatments on the crystalo-chemical characteristics of the mineral part of the soil adsorbent. (2005 r.) Institute of Agrophyscis PAS, Lublin, "Physicochemical character of soil adsorbent" 2005, 60-72