Any help?

Finally I got it. I was searching the difficult. It was so easy...

Any hint, besides the previous

Thanks for the post. But I can't think anything. I can't find the connection. I leave it for awhile. If you see the book, give me a hint. Thanks anyway.

As someone else said: Top rows are 7 bottom lines are 5. What I cant get it!! I cant understand what I'm looking for. That is my problem.

Any hint? I can't understand.

Thanks again. Sorry for the spoiler. I don't realize it. I'll be careful. Thanks.

I see the definition of spine. I have solved the keys in order. How does it help me?

At last. Thanks a lot!!!!!