> Hans Hagen <mailto:pragma@wxs.nl>
> 8. September 2016 um 18:17
>
>
> then just look in the log file
>
> \in[foo]
>
> produces
>
>
> references > start problematic references
>
> references > unknown >    1: [][foo]
>
> references > stop problematic references
Duplicates are only listed with user set references, sections or floats 
are mentioned in the log.

     \starttext

     \chapter[sec:first] {First chapter}
     \chapter[sec:second]{Second chapter}
     \chapter[sec:first] {Third chapter}

     \pagereference[ref:page]
     \pagereference[ref:page]

     \stoptext

shows only

     references > redundant reference 'ref:page'

but 'sec:first' is missing.

Wolfgang