This is an example of how to access ebooks through Springer. In the OPAL catalog, a Springer ebook will appear as "OHIOLINK SPRINGER EBOOKS." Clicking on the "View Online" link at the bottom of that entry will take you to a page that looks like this:
There is a large, blue button on the righthand side which gives you the option to download the book as a PDF. Optionally, below that button, there is a link which will allow you to download an EPUB file. Clicking the blue PDF button will open a screen in your PDF viewer, where you will have the option to download the ebook.