SPECTROPOLARIMETRY OF THE 3-MU-M ICE FEATURE IN MOLECULAR CLOUDS .2. GL 2591, GL 2136, W33A AND ELIAS 29 (RHO-OPHIUCHI DARK CLOUD) - Hough, J; Whittet, D; Sato, S; Yamashita, T; Tamura, M; Nagata, T; Aitken, D; Roche, P (1989)