PS1 & PSP Games Arrive on Asian PlayStation Store for PS4 / PS5 | PSXHAX - PSXHACKS
How To Play PS1 Games On PS4 Jailbreak 7.02 Or Lower - YouTube
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
PS4 Backwards Compatibility: Can You Play PS1, PS2, and PS3 Games on PS4?
List: All PS1, PS2, and PSP classics on PS Plus Premium
PS4 may soon play your favorite PS1 and PS2 games in native 1080p | Extremetech
Great News! PS1 Games on PS Plus Premium Are 60Hz NTSC Versions | Push Square
PS1 games on PS4: Which PlayStation 1 games can you play on PlayStation 4?