As you see, the current version of PEN extended does not contain the problems in year 2008.
Please, send us number theory problems in national math olympiads ( taken in between September ’07 and June ’08 ) and selection test for IMO 2008 from your country. The problems we receive will be included in the first edition of PEN extended with contributor’s name. The TeX format is available HERE.
from PEN TEAM
Before submitting your TeX file, check out the following list. The national codes are from http://www.imo-official.org