UPPER LIMITS FOR THE DECAY OF TAU-LEPTONS INTO ETA-MESONS - ALBRECHT, H; BOCKMANN, P; GLASER, R; HARDER, G; KRUGER, A; NIPPE, A; REIDENBACH, M; SCHAFER, M; SCHMIDTPARZEFALL, W; SCHRODER, H; SCHULZ, HD; SEFKOW, F; et al. (ZEITSCHRIFT FUR PHYSIK C-PARTICLES AND FIELDS, 1988)