diff --git a/papers/doc/7-systems/ym2203.md b/papers/doc/7-systems/ym2203.md
index 18f051e8d..6b0bbf8d9 100644
--- a/papers/doc/7-systems/ym2203.md
+++ b/papers/doc/7-systems/ym2203.md
@@ -1,11 +1,11 @@
 # Yamaha YM2203 (OPN)
 
 a cost-reduced version of the YM2151 (OPM).
-it only has 3 FM channels instead of 8 and removes the LFO.
+it only has 3 FM channels instead of 8 and removes stereo, the LFO and DT2 (coarse detune).
 
 however it does contain an AY/SSG part which provides 3 channels of square wave with noise and envelope.
 
-this chip was used in the PC-88/PC-98 series of computers, and in some arcade boards.
+this chip was used in the NEC PC-88/PC-98 series of computers, the Fujitsu FM-7AV and in some arcade boards.
 
 several variants of this chip were released as well, with more features.
 
diff --git a/papers/doc/7-systems/ym2608.md b/papers/doc/7-systems/ym2608.md
index 51720d1b0..736258a38 100644
--- a/papers/doc/7-systems/ym2608.md
+++ b/papers/doc/7-systems/ym2608.md
@@ -1,8 +1,8 @@
 # Yamaha YM2608 (OPNA)
 
-like YM2203, but with twice the FM channels, an ADPCM channel and built-in drums ("rhythm")!
+like YM2203, but with twice the FM channels, stereo, an ADPCM channel and built-in drums ("rhythm")!
 
-it was one of the available sound chips for the PC-98 series of computers.
+it was one of the available sound chips for the NEC PC-88VA and PC-98 series of computers.
 
 the YM2610 (OPNB) and YM2610B chips are very similar to this one, but the built-in drums have been replaced with 6 sample channels.