Systematics and ecology of Stilestrongylus freitasi Durette-Desset, 1968 and Hassalstrongylus multiovatus n. sp. (Nematoda: Nippostrongylinae) from Akodon simulator (Cricetidae) in Tucuman (Argentina). Research and Reviews in Parasitology, 52(1-2), June 1993: 51-55. 52 [Zoological Record Volume 131]