Report: PS1,PS2 Games Are Coming to PlayStation 4 With Updated Visuals | Complex
PlayStation 4 and PSVita Releases: PCSX-R port for the PS4 has been released allowing you to emulate PS1 games and ElevenMPV 2.1.0 released with many fixes! - Wololo.net
PS1/PS2 games heading to PlayStation 4 | Eurogamer.net
Sony Playstation 1 PS1 Gray Original japan + 4 games Tested Working SCPH-5502. | eBay
Is PS5 Backward Compatible: Does it Play PS1, PS2, PS3, and PS4 Games?
PlayStation 4 - Wikipedia
Can you play PlayStation 1 games on a Playstation 4? - Quora
PS5 Won't Support PS3, PS2 Or PS1 Games, Sony Says