I have different sections of my CV for different items. Posters and presentations has their own section and I cite them like so:
Authors, Title, Name of the Conference Where I Presented, (what I presented)
Authors are listed as they appear on the poster or abstract, last name first. In the parenthesis I put "Poster" if poster, etc.
I also have a Publication section if the item has been published in a journal (i.e., it has a Pubmed citation). I will use roughly the PubMed citation and at the end annotate, as above, whether it is an article or abstract.
Instead of on secondaries, I listed my pubs on AMCAS as ECs. Click the link in my signature and scroll down for how I listed them.
I have to second being very clear on whether you've done a poster, full-length article, whatever. It's easy to give the wrong impression by not being clear, and the people who review your app will notice.