Koyumdzheva 1978. On the systematics of the genus Hirstionyssus Fonseca, 1948 (Gamasoidea, Hirstionyssidae) with a description of a new species Hirstionyssus improvisus sp. n. from the Bulgarian mouse-like dormouse. Acta Zoologica Bulgarica, No. 11 1978: 49-54