Add citation information

CITATION.cff

@@ -0,0 +1,29 @@
+cff-version: 1.2.0
+message: "If you use Proteus, please cite it as below."
+authors:
+- family-names: "Bognar"
+  given-names: "Marton"
+  orcid: "https://orcid.org/0000-0002-8641-7549"
+- family-names: "Noorman"
+  given-names: "Job"
+- family-names: "Piessens"
+  given-names: "Frank"
+  orcid: "https://orcid.org/0000-0001-5438-153X"
+title: "Proteus: An Extensible RISC-V Core for Hardware Extensions"
+url: "https://github.com/proteus-core/proteus"
+preferred-citation:
+  type: conference-paper
+  authors:
+  - family-names: "Bognar"
+    given-names: "Marton"
+    orcid: "https://orcid.org/0000-0002-8641-7549"
+  - family-names: "Noorman"
+    given-names: "Job"
+  - family-names: "Piessens"
+    given-names: "Frank"
+    orcid: "https://orcid.org/0000-0001-5438-153X"
+  month: 6
+  title: "Proteus: An Extensible RISC-V Core for Hardware Extensions"
+  year: 2023
+  conference:
+    name: "RISC-V Summit Europe '23"

README.md

@@ -2,6 +2,16 @@
 
 For a quick introduction to Proteus, and to cite this work, please check [our extended abstract](https://mici.hu/papers/bognar23proteus.pdf) presented at the RISC-V Summit Europe '23.
 
+```bibtex
+@inproceedings{bognar23proteus,
+  author    = {Bognar, Marton and Noorman, Job and Piessens, Frank},
+  title     = {Proteus: An Extensible RISC-V Core for Hardware Extensions},
+  booktitle = {{RISC-V} Summit Europe '23},
+  month     = jun,
+  year      = 2023
+}
+```
+
 ## Get started with Proteus
 
 - [Installation](#installing-proteus)