[NTG-context] compiling the mkiv-publications manual

Hello list, I'm trying to compile the mkiv-publications manual from the ConTeXt distribution. Running context mkiv-publications stops with the error: ... tex error > tex error on line 58 in file publications- database.tex: ! Undefined control sequence l.58 \startBTX ... 55 56 A \BIBTEX\ file entry looks like this: 57 58 >> \startBTX 59 @Article {sometag, 60 author = "An Author and Another One", 61 title = "A hopefully meaningful title", 62 journal = maps, ... maybe I need to specify some options in the command line, to make ConTeXt aware of the \startBTX macro. Greetings, Massi