Docear4Word is based on the citation style language which is used by many other popular reference mangers, too (e.g. Zotero, Mendeley, and Papers). Therefore, all CSL styles from any of the other reference managers can be used with Docear4Word. To do so, search the Zotero style repository and download the style you want to your style folder. The style folder typically is located at c:\ProgramData\Docear4Word\Styles\ (you can always see the actual path in the about dialog of Docear4Word, see screenshot). Developing your own citation styles is also possible.