Credits
To begin, as is stated on the front page, credit for most of the data goes to the Slick Productions FF4 R&D Forum, in general.
I'll list everyone who has data contributed on the site in alpahbetical order, along with the data(docs) they contributed:
Deathlike2: Elemental Ref. Guide, Attack Algo, Avenger Sword, Bow & Arrow Data, Magic Algo, Sylph Summon, (Part of)Random Spell Notes, Caignazzo, HP% Spells, Monster Spells, Back Row Bugs, and the entire "Statuses" section
Dragonsbrethren: Window Data, Weapon Bits, and Item Drops(FF4ET)
Edea: Lv. up data, Magic list IDs
Entroper: Monster Reference XLS
JCE3000GT: FF2US Hacking Doc, Pointer Data, Chest Offsets, FF2 Music, FF4 Music, FF2US Item Drops, Monster Img Data, and Pinkpuff Data
Paladin: Item Compendium XLS
Phoenix: Shadow Party Data, Event Offsets, Element Data, Attack Sequence Differences, Weapon Changes, Spell ASM, (Part of) Random Spell Notes, Atk Sequ Group Data, Attak Sequences, Enemy Condition Indicies, Command Disabling by Status
Zyrthofar - Item Drops(FF4/2us)
Bond697 - Monster Location Guide