DOnkr PLO from scratch series, and Hwangs books.
Also this book http://www.amazon.com/Mastering-Pot-Limit-Omaha-Aggressive-Approach/dp/1909457310

And a bunch of essential vids :)

Definitely agree with LOL_MATH - DonkR series, its very solid(and Free). Also, Jeff Hwangs The Big Play Strategy is a good starting point.

Mastering pot limit omaha is a great book, but i would learn the concept of PLO first before reading this book.

hi! I can recommend secrets of short handed pot limit omaha, but not when you are beginning because it says a lot of advanced high stakes concepts which will confuse you . But when you are a bit more experienced, you can start reading it, but be careful, when applying advanced stuff against weaker and less thinking players

thanks guys ı will start from DOnkr PLO from scratch