2 literature references for Isohypsibius montanus (Mihelcic, 1938):

Author: Guidetti, Roberto, and Roberto Bertolani
Year: 2005
Title: Tardigrade taxonomy: an updated check list of the taxa and a list of characters for their identification
Source: Zootaxa, issue 845
Author: Ramazzotti, G., and W. Maucci
Year: 1983
Title: Il Philum Tardigrada: III edizione riveduta e aggiornata
Source: Memorie dell'Istituto Italiano di Idrobiologia Dott. Marco de Marchi, vol. 41