Dear all, Is it possible to have a sort of « local references for formulas » or else to clear previous references to formulas at a certain point? In a chapter where a certain number of exercices and formulas are to be numbered, assume I have the following minimal example %%%%%%%%% begin \starttext Exercice 1. Prove that if $ab=ba$ and $2ab=0$ then \placeformula[eq:1] \startformula (a+b)^2 = a^2 + b^2. \stopformula Using the identity (\in[eq:1]) prove that $(a=b)^{2n} = a^{2n} + b^{2n}$. \blank[big] \hrule \blank[big] Exercice 2. Prove that for any integer $n$ \resetnumber[formula] %\reset[formulas][references] \placeformula[eq:2] % I would like the reference to be [eq:1] \startformula (\cos(x) + {\rm i}\sin(x))^n = \cos(nx) + {\rm i} \sin(nx). \stopformula Using the identity (\in[eq:2]) % I would like here to say [eq:1] compute $\cos{3x}$. \stoptext %%%%%%%%% end I would like to be able to have the equations numbered within each exercise (which is in fact defined through an enumeration environment), and be able to have the reference to each formula « local » within that exercise. The resaon is that the execises and problems may have several equations which are referenced to with [eq:1] through [eq:10] (say…), and have been prepared and given previously to students on independent sheets. When I want to give out a booklet of all the exercises, then it would be handy to have such a feature. I understand that I am not being very clear… Hope someone would understand what I mean and need :-) Best regards: OK