■公式サイト
Pacific Cycles Japan
https://pacific-cycles-japan.com/birdy/index.html
Pacific Cycles
https://www.pacific-cycles.com/birdy
Riese & Muller
https://www.r-m.de/en-en/bikes/birdy/

■説明書・カタログ
https://www.r-m.de/en-en/service/downloads/

■前スレ
birdy & BD-1 #003
https://medaka.5ch.net/test/read.cgi/bicycle/1595116754/
birdy & BD-1 #004
https://medaka.5ch.net/test/read.cgi/bicycle/1662290059/