Detection of solid ammonia, methanol, and methane with ISOPHOT J. Gürtler, U. Klaas, Th. Henning, P. Ábrahám, D. Lemke, K. Schreyer and K. Lehmann A&A, 390 3 (2002) 1075-1087 Published online: 14 August 2002 DOI: 10.1051/0004-6361:20020772