First identify the object
A link can lead to a whole proceedings volume, an individual paper or a record about the conference. These are related objects, not interchangeable citations. Crossref's proceedings guide separates event information, proceedings information and individual paper records. Its paper metadata requires contributors, title and DOI; other fields provide further context.
The DOI Foundation describes the identifier's job as keeping track of an object over time. The identifier is useful because it makes a reference easier to follow, not because its presence explains the object's entire editorial history.
Then investigate the review claim
If a page calls a paper peer reviewed, look for the relevant year's venue policy and the paper's actual track. Do not substitute the conference's general reputation for those particulars. A useful review note would identify the policy inspected and explain what it says about evaluation. If that evidence is unavailable, write that the process is unconfirmed rather than guessing.
This is a proposed verification method. The Crossref schema documents registration; it is not evidence that a particular conference did or did not conduct review.
Keep versions from merging in your notes
When a preprint and a proceedings paper have similar titles, compare their contents before transferring a claim from one to the other. Retain the authors, title, version, event, publication date and identifier of the object actually read. Check whether a cited result appears in that version. A well-kept citation should let the reader inspect both the research and the limits of what you verified about its publication.