How can I publish paid and free ibooks in my country?

As a university in Turkey, we are planning to publish paid and free ibooks on the iBooks Store. The problem is when we check the ibook store from our İOS devices we can only see historical and royalty free books, plus the demo ibook "Life on Earth" and "Yellow Submarine" from Apple.

What does that mean? Why is the iBook Store limited to Turkish customers? And aren't we will be able to publish our content via Apple Store?