TY - RPRT TI - Environmental factors and mechanisms controlling degradation of Tb(III) chelates: development of effective new Tb phosphors for postage stamp use AU - Parks, E J AU - Olson, G J AU - Brinckman, F E PY - 1985 PB - National Bureau of Standards CY - Gaithersburg, MD SN - NBS IR 85-3132 DO - 10.6028/NBS.IR.85-3132 ER -