Change bibliography label in Beamer

Question

I am using

\bibliographystyle{plain}
\bibliography{references}

to include references in the file references.bib. This is what I get I want to change the icons one by one. In other questions they use

\setbeamertemplate{bibliography item}[article]

but this changes all the icons at once.

¿How can I change each icon individually? I want to put my own icon, not the default ones since they don't match the style of the presentation. Ideally without using thebibliography since I already have the file references.bib.