발명 공보 PDF 2022-12
http://www.dprkmedia.com.009911uv0007.erf.sbb.spk-berlin.de/Uploaded/Journal/2119/KPJ_83388.pdf
Journal of Invention (dprkmedia) December 31, 2022
http://www.dprkmedia.com.009911uv0007.erf.sbb.spk-berlin.de/Uploaded/Journal/2119/KPJ_83388.pdf