Conner JP, Evans WD, Belian RD (Sep 1969). "The Recent Appearance of a New X-Ray Source in the Southern Sky". Ap J. 157: L157–9. Bibcode:1969ApJ...157L.157C. doi:10.1086/180409.
Conner JP, Evans WD, Belian RD (Sep 1969). "The Recent Appearance of a New X-Ray Source in the Southern Sky". Ap J. 157: L157–9. Bibcode:1969ApJ...157L.157C. doi:10.1086/180409.
Dunning, Brian (26 January 2010). "Skeptoid #190: The Bell Island Boom". Skeptoid. Retrieved 22 June 2017. N.B. quote: "They also picked up large lightning flashes, and it was in part from the Vela satellites that we learned about lightning superbolts. About five of every ten million bolts of lightning is classified as a superbolt, which is just what it sounds like: An unusually large bolt of lightning, lasting an unusually long time: About a thousandth of a second. Superbolts are almost always in the upper atmosphere, and usually over the oceans."