"requires a detailed scientific justification" or "requires detailed scientific justification"

Question

The use of a different reference drug requires a detailed scientific justification, as well as additional documents and data.

The word "justification" is marked as both countable and uncountable in dictionaries, and I'm not sure whether a is necessary here.

Maybe it works both ways, with or without "a"? I feel like with "requires" it works both ways, while with "calls for" it feels like "a" is necessary.

The use of a different reference drug calls for a detailed scientific justification, as well as additional documents and data.

Answer 1

The word justification is an uncountable noun when it means

the action of showing something to be right or reasonable ‘Such a position is, I suppose, formally possible but it - and not extrapolation - requires special justification.’

but it is countable when it means

good reason for something that exists or has been done-‘all these incidents were used again as a justification for my sacking’

My source was:www.en.oxforddictionaries.com.

Therefore,I would not use the article a.