text: These [[ evaluations ]] are probably the only << NL evaluations >> other than the series of Message Understanding Conferences -LRB- Sundheim , 1989 ; Sundheim , 1991 -RRB- to have been developed and used by a group of researchers at different sites , although several excellent workshops have been held to study some of these problems -LRB- Palmer et al. , 1989 ; Neal et al. , 1991 -RRB- .