Dzakowic, G.; Kan, T.; Kuenning, R. & Schlitt, L. Design study of high average power (20-100 watts) pulsed nitrogen lasers at lambda = 3371 A, report, February 27, 1975; (https://digital.library.unt.edu/ark:/67531/metadc878768/m1/1/: accessed December 10, 2018), University of North Texas Libraries, Digital Library, digital.library.unt.edu; .