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: 
There's not really a "grammatical" justification for the choice, but idiomatically, we [almost always](http://books.google.com/ngrams/graph?content=split%20in%20sections,split%20into%20sections&year_start=1700&year_end=2000&corpus=0&smoothing=3) use *"into"* with *"sections"*...

![enter image description here](https://i.stack.imgur.com/1n8Dv.png)

...whereas with *"half"*, for example (there aren't many such examples), it's [the other way around](http://books.google.com/ngrams/graph?content=split%20in%20half,split%20into%20half&year_start=1700&year_end=2000&corpus=0&smoothing=3)

![enter image description here](https://i.stack.imgur.com/WAkM8.png)

In fact, apart from *"half"* I'm not sure there's any other split you can make where *"into"* isn't preferred. If you compare [split in/into two](http://books.google.com/ngrams/graph?content=split%20in%20two,split%20into%20two&year_start=1700&year_end=2000&corpus=0&smoothing=3), the preference isn't quite so marked - but that's probably influenced by the unusual usage with *"half"*. As you go to bigger numbers, the preference for *"into"* [is overwhelmingly reasserted](http://books.google.com/ngrams/graph?content=split%20in%20three,split%20into%20three&year_start=1700&year_end=2000&corpus=0&smoothing=3).

For a (weak) justification of the idiomatic preference for *split **into*** over *split **in***, I suggest that in numerous "compound verbs" *(lapse into a coma, descend into chaos, developed into full-blown AIDS, etc.)*, the *"into"* component strongly associates with "transformation" of the primary subject.

That association very much involves the "sub-component *"to"*, which can pass muster on its own in things like *turn to stone, bring to focus, etc.*. With those, you can get away with *"into"*, but you couldn't possibly use *"in"*.
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.