발명 공보 PDF 2023-1
http://www.dprkmedia.com.009911gx0827.erf.sbb.spk-berlin.de/Uploaded/Journal/2119/KPJ_83727.pdf
Journal of Invention (dprkmedia) January 31, 2023
http://www.dprkmedia.com.009911gx0827.erf.sbb.spk-berlin.de/Uploaded/Journal/2119/KPJ_83727.pdf