Author,Title,Journal,ISSN,Publisher,Date,Volume,Number,Page,URL,URL(DOI) Ouchi Yasuhiro and Yamasaki Yoshio,Characteristics of acoustical horn with ring-shaped aperture,THE JOURNAL OF THE ACOUSTICAL SOCIETY OF JAPAN,03694232,Acoustical Society of Japan,2017,73,1,5-11,https://cir.nii.ac.jp/crid/1390282681542812032,https://doi.org/10.20697/jasj.73.1_5