1. “In strict vocabulary a tunnel has one opening in each end. If there is just one opening, which is normal in horizontal underground nuclear testing, it is correctly called an adit. As the discrepancy is here not very important the term “tunnel” is used for both”.
2. Murphy, J. R., Kohl, B. C., Stevens, J. L., Bennett, T. J. and Israelsson, H. G. “Exploitation of the IMS and Other Data for a Comprehensive, Advanced Analysis of the North Korean Nuclear Tests”. (paper presented at the 2010 Monitoring Research Review Orlando, Florida, 21–23 September 2010),
3. A long distance measurement of radioxenon in Yellowknife, Canada, in late October 2006
4. Murphy, J. R.op. cit