Author,Title,Journal,ISSN,Publisher,Date,Volume,Number,Page,URL,URL(DOI) Ohira Takashi,Load impedance perturbation formulas for class-E power amplifiers,IEICE Communications Express,2187-0136,"The Institute of Electronics, Information and Communication Engineers",2020-10-01,9,10,482-488,https://cir.nii.ac.jp/crid/1390567172584127616,https://doi.org/10.1587/comex.2020xbl0085