The letter at the end of memory module ratings

[PornoSatan]

Are these right?

PC2-5300R (Registered)
PC2-5300F (Fully Buffered)
PC2-5300U (Unbuffered)
PC2-5300S (Small Outline)

What others are there?

nevermind, Wikipedia entry had it covered:

https://en.wikipedia.org/wiki/DDR2_SDRAM#Chips_and_modules