[NTG-context] first and last line number on page

Hi there, with the following sample: \starttext \startlinenumbering \dorecurse{10}{\input zapf\par\input knuth} \stoplinenumbering \stoptext I would like to have a header that contains the first and last line number on the page. Is there any way to do that? (The ConTeXt reference manual and the wiki seem not to have an answer to this question.) Many thanks for your help, Pablo -- http://www.ousia.tk