- Cărți electroniceEurypterids of the Devonian Holland Quarry Shale of OhioErik Norman Kjellesvig-Waering
- Cărți electronicePennsylvanian invertebrates of the Mazon Creek Area, IllinoisErik Norman Kjellesvig-Waering
- Cărți electronicePennsylvanian invertebrates of the Mazon Creek Area, IllinoisErik Norman Kjellesvig-Waering
- Cărți electroniceEurypterids of the Devonian Holland Quarry Shale of OhioErik Norman Kjellesvig-Waering