This template should always be substituted (i.e., use ((subst:Cite book/Danish))). Any accidental transclusions will be automatically substituted by a bot.
This template attempts to translate the Danish-language template da:Skabelon:Kilde bog to the English-language template ((cite book)). ((Kilde bog)) is a redirect to this template. Because da:Skabelon:Cite book (also used at da.wiki) has the same name as ((cite book)), that template is not translated. To translate a da.wiki ((cite book)) template, rename the template to ((cite book/Danish)).