I found this online after a conversation with my teacher about the technique of Alfredo Kraus. I am currently experimenting with some of the images within the masterclass and will report back with my findings. So far so good, though I’ve only been working on one aria with them.
[Note: There are a few typos within the transcript. For example, he mentions singers singing the vowel "c". Well, of course there is no vowel "c", and judging by the context clues (thank you first grade!) he means the vowel [e]. ]