HI am trying to find a way to extend article metadata. I need one or two custom fields, and I want to be able to access those data trough oai nlm, like in this journal:
http://casopisi.junis.ni.ac.rs/index.php/index/oai?verb=GetRecord&metadataPrefix=nlm&identifier=oai:casopisi.junis.ni.ac.rs:article/1849
I also need references listed as metadata.
As a bonus, it would be nice to show that data on article page, but it is not priority at this moment.
I am using ojs 2.4.8, and still not planning to upgrade to 3.x
i have some php coding experience and any suggestion or hint will be appreciated. 
Thanks
p.s.
sorry for bad english