Create a Citation Style

Elivando Carvalho de Mesquita said:

Is it possible to create a citation style for custom books?

As Graham said, we can't create citation styles. I'm stumbling over your "custom books". The citation styles work for all books equally (there may be master data errors or bugs, but in principle that's the case).

Why are you asking for "custom books" - do you mean Personal Books? The citation styles work for them as well, the point is to include the necessary data when building the book (such as publishing year, publisher with location etc)