Dutch Acol
Here is the
non-frame based version of the Dutch Acol System.
Dutch Acol is totally different from English Acol. Dutch Acol uses a strong No Trump and a four card minor is opened in preference to a 4 card major.
The system is unsound and most Dutch players have moved onto playing 5-card majors.
They still call it Acol but is is, in reality, Standard American.