RetroC temporal classification challenge for Vietnamese

Guess the publication year of a Vietnamese text. The metric is root mean square error.

submitter when description dev-0/RMSE test-A/RMSE
p/tlen 2016-03-13 09:04 Vowpal Wabbit -nn 6 on up to 4-grams (for characters) 6.3349653462824 7.23130434217645
p/tlen 2016-03-13 08:51 by year references 13.9641131798107 14.4404473927674
p/tlen 2016-03-13 08:43 null model (always return 1990.0) 18.7680103485255 21.0541773293699