[1]
K. Akiyama, M. Ogawa, and C. Suetake, “On ${\rm STD}_6[18,3]$’s and ${\rm STD}_7[21,3]$’s Admitting a Semiregular Automorphism Group of Order 9”, Electron. J. Combin., vol. 16, no. 1, p. R148, Dec. 2009.