I've been trying to nail down all references to Ye'Cind I could find. This is what I have for a chronological bibliography:
Dungeon Master's Guide (1979)
"Spells Between The Covers," Dragon Magazine 82 (Feb84)
Book of Artifacts (1993)
Greyhawk Player's Guide (Jun98
Warriors of Heaven (1999)
"All Oerth's Artifacts," Dragon Magazine 299 (Sep02)
Living Greyhawk Gazetteer (2000)
"The Gods of Oerth," Living Greyhawk Journal 3 (Feb01)
The magority of the info on Ye'Cind is in LGG, with info on his Recorder coming from BoA. The other sources just add minor facts (WoH) or repeat information that these two have.
Can anyone think of a reference I have missed?