[NTG-context] New bibligraphy style

Hello, I am using the bib module and I want to redefine the display style for the references. I have therefore created a new file "bibl-ris.tex" which I have put in the same folder as bibl-apa.tex and the other existing ones. In my environment file I have \setuppublications[alternative=ris]. Unfortunately, I get the error file bibl-ris not found, unknown style ignored Where should I put my bibl-ris file, or is there something else I need to do before it can find my file? Thanks. Richard