- E-bookThe Frontier Boys in the Grand Canyon A Search for TreasureWyn Roosevelt
- E-bookFrontier Boys in FriscoWyn Roosevelt
- E-bookFrontier Boys on the Coast or in the Pirate's PowerWyn Roosevelt
- E-bookThe Frontier Boys in the Sierras Or, The Lost MineWyn Roosevelt
- E-bookFrontier Boys in the South SeasWyn Roosevelt
- E-bookThe Frontier Boys in the Grand Canyon; Or, A Search for TreasureWyn Roosevelt
- E-bookThe Frontier Boys in the Sierras; Or, The Lost MineWyn Roosevelt