When searching for these PDFs, you will often encounter the (Annotated Ada Reference Manual). This version includes the standard text plus "rationale" comments explaining why certain design decisions were made. For a developer trying to understand the intricacies of the Ravenscar Profile or the SPARK subset, the AARM is actually more valuable than the raw standard.
The most sought-after "Ada full text PDF" in this domain is Ada Lovelace’s translation and expansion of Luigi Menabrea’s article on Charles Babbage’s Analytical Engine. Published in 1843, this document contains what is widely considered the first computer algorithm. ada full text pdf