IETMs are electronically combined and given hyperlinks. We may consider PDF files as Level 1, Indexed PDFs as Level 2, HTML Based indexed files will be considered as Level -3. Levels -1 and 2 or no more used as deliverables. Level -3 can be used when the pages are 3000 to 4000. https://www.codeandpixels.net/blog/what-is-ietm-and-what-is-not-ietm/