Vikings Academy by S. T. Bende

When seventeen-year-old Saga Skånstad discovers an antique dagger, she's instantly sucked into a world where Vikings rule the seas and dragons roam the skies, and the only thing more dangerous than the chief who takes her captive is the rival who steals her away. The heir of Norway's most feared tribe is fierce, cold, and absolutely unyielding. With intruders encroaching upon his borders, Erik Halvarsson has little patience for the girl whose ignorance threatens his very existence. He enlists Saga in the magical Valkyris Academy, where she learns the skills she'll need to protect herself from foreign raiders and domestic terrors. But nothing can protect her from falling for the one guy in all the world she's absolutely forbidden to choose . . . or from risking everything to unlock the secrets that haunt him. When darkness threatens Saga's new home, she must decide whether to return to the life she's always known, or fight for a love she never could have imagined. Her decision will determine a legacy--not only for Saga, but for the world she never knew she was fated to lead.

Ursa Kane by Stacy Bender

On her way to a martial arts convention, Danielle Kane's plane crashes on an island in the Bermuda Triangle with cities trapped in time. She is furious to learn that on this island teetering on the brink of civil war, women are chattel. The sixteenth century Spaniards want to lock her in a tower. The fourteenth century pirates want to enslave her. The Inca Indians would worship her as a god. The World War Two soldiers aren't sure what to make of her. None of them are ready for a modern woman.