Post 442105 (https://www.thevespiary.org/talk/index.php?topic=9038.msg44210500#msg44210500)
(DRIVEN: "NaOCN from urea and sodium carbonate", Methods Discourse) has most of the links to procedurals for NaOCN, whilePost 354295 (https://www.thevespiary.org/talk/index.php?topic=9285.msg35429500#msg35429500)
(Bandil: "trans-4-MAR synth w/o cyanogenbromide writeup!", Methods Discourse) is the famous 4-MAR thread.