Question: In the sentence

> 
> I have a bibliography page which I'd like to **split in/into** sections
> 
> 
> 

which would you rather use: *split in* or *split into*?

Why?

Answer: 
We generally use 'into' to talk about directions and destinations, while we use 'in' to talk about the positions of thing. So you have to use 'split into' in your example because the destinations of the bibliography are the sections. 
However we might use:
(1) 'into' when we think of the division (split) itself; 
(2) 'in' when we think more at the end of division.
Split in sections does not make any sense - you would have to split something **into** sections.