I saw it in a website in flash format.
Files were not downloadable. I managed to download them with a few trick.
I converted flash files into flv files.
Found the text frames in each flv file one by one. Saved and renamed each one. (About 350 of them.)
Created PDF file. The original file was more than 300MB.
Got an image resizing tool, but it was limited edition. Found crack. Resized images by it.
Created an optimized version of the PDF. It's now much smaller. But some small characters look blurry. They look very clear in the original PDF file.
It took lots of time of mine, but worth it. Now I'm studying with it.