Hi, while I was trying to respond to the recent message by José Francisco,I stumbled across the following post: http://lists.wfu.edu/pipermail/gretl-devel/2013-March/004379.html which suggests to do something like: <hansl> open data9-7 list foo = PRIME(2 to -2) print foo -o </hansl> And indeed this works. However, PRIME(+3 to +2) fails, instead you have to swap the numbers around to PRIME(+2 to +3). (PRIME(-3 to -2) also fails.) So it seems that when you want _only_ leads or _only_ lags, you have to provide the numbers by increasing *absolute* value. I'm not sure I see the deeper logic there. I would vote for accepting every ordering, or to go for decreasing (non-absolute!) value as in the standard case (-1 to -4). Thanks, sven