A. D.  Nguyen and Sierwad, P., ?Distribution and descriptive characteristics of the two giant pill millipedes of the genus Sphaerobelum Verhoeff, 1924 (Diplopoda, Sphaerotheriida, Zephroniidae) in Vietnam?, TAP CHI SINH HOC, vol. 41, no. 1, pp. 9?17, 2019.