Mahou Shoujo Lyrical Nanoha StrikerS the Comics

Chapters 1-3 are the events that occurred between the end of A's and the start of StrikerS. Chapters 4-12 are side stories about the characters. Chapters 13 & 14 are the events that occurred after the end of StrikerS. Chapter 15 is a special from Megami September 2009 (also events after the end of StrikerS).