Merge pull request #19 from anuket-project/walterkozlowski-patch-2

Update refs.bib

doc/ref_model/refs.bib

@@ -338,3 +338,8 @@ @misc{gsmafs16
 	howpublished = {GSMA FS.16 v2.2},
 	url = {https://www.gsma.com/security/resources/fs-16-network-equipment-security-assurance-scheme-development-and-lifecycle-security-requirements/}
 }
+
+@misc{ngagreeng,
+	title = {{Next G Alliance Green G: The path towards sustainable 6G}},
+	url = {https://nextgalliance.org/white_papers/green-g-the-path-towards-sustainable-6g/#:~:text=Green%20G%3A%20The%20Path%20Toward%20Sustainable%206G%20shows%20how%20the,while%20accelerating%20progress%20toward%206G/}
+}