Dijkstra Manuscript Archive
cs.utexas.edu
cs.utexas.edu
All of this translates directly into developing a taste for elegant (programming) interfaces and well structured architectures.
In the past, I put together a curated list of pdfs for anyone who wants to start studying and practicing Dijkstra's mathematics. Here is what I recommend:
EWD1300 - The notational conventions of the mathematics : http://www.cs.utexas.edu/users/EWD/ewd13xx/EWD1300.PDF
After that, I have this collection of EWDs and other documents that offer the best, graded, introductions to the idioms and concepts of Dijkstra's mathematics:
I don't recall using imperative programming languages until at least sophomore year.