[NTG-context] \in, \at, and labletext

Dear List, In the Documentation IntroCTX_eng_s.pdf at page 170 , I found the two examples with \in and \at, and also the lable. The Problem is, that in the following sentence only the number (3.1) is a placed formula in an example, should have a link. Without the brackets. The sentence says: Task 1: Formulate equivalents according to rule (3.1): Sorry, I have no example. Uschi