Pedro Martínez: yes very ugly :)
we have 2 plural forms in dutch indeed -en and -s .. most words use -en though i think ... i dont know of any rule to know if i should use -s or -en .. thats pure 'feeling' :)
(i guess foreign words use -s ?)

'articles' ? hmm never knew about that .. no wonder i couldnt find it :)

i also see a lot of people (in every job, level of education, etc.) use 'een hele mooie auto' while it should be 'een heel mooie auto'
(a very beautiful car)

this is because 'heel' in that sentence points to 'mooie' and not to 'auto' ... its a personal pet peeve of me ... every time i hear it on the news, see it in the news paper (its even written down! not just speech), etc. i yell out! :)
(my gf recently joins me in the yelling ;))