On the orbital period of the cataclysmic variable V592 Herculis
  We present a spectroscopic study of the long-recurrence-time dwarf nova V592 Herculis based on observations obtained during its August 1998 superoutburst.   From the analysis of the radial velocities of the Halpha emission line we find a most likely orbital period of 85.5 +- 0.4 minutes, but the 91.2 +- 0.6 minutes alias cannot be completely discarded. Both periods imply a very small period excess and supports the brown-dwarf like nature of the secondary star. 
R.E. Mennickent, C. Tappert, R. Gallardo, H.W. Duerbeck, T. Augusteijn