A Technique for Simultaneous Measurement of Circular and Linear   Polarization with Single-Channel Polarimeter
  The algorithm is described, which have been used for photo-polarimetric monitoring of various astronomical objects - cataclysmic variables, asteroids, comets. 
Sergey V. Kolesnikov, Vitalii V. Breus, Nickolay N. Kiselev, Ivan L.   Andronov
astro-ph.IM