Arthur Conan Doyle's Favorite Adventures
The Speckled Band	SPEC
The Red-Headed League	REDH
The Dancing men	DANC
The Final Problem	FINA
A Scandal in Bohemia	SCAN
The Empty House	EMPT
The Five Orange Pips	FIVE
The Second Stain	SECO
The Devil's Foot	DEVI
The Priory School	PRIO
The Musgrave Ritual	MUSG
The Reigate Puzzle	REIG
The 4-letter abbreviations were begun by J. Finley Christ years ago. Sherlockians know the entire list and often use them in quotes or articles.
Thanks to the Nashville Scholars for the link.