Small audio amplifiers BC637
I want to duplicate the small audio amplifiers at https://ludens.cl/Electron/audioamps/AudioAmps.html
but he uses a BC637 & BC640 pair. They have the BC640 at mouser but NOT the BC637. What should I use instead for the BC637?
Or do you know a reliable place to get real ones?
(Or is there another equivalent complimentary pair that would be ideal to use instead?)