Fibration by non-smooth projective curves of arithmetic genus two in   characteristic two
  Looking in positive characteristic for failures of the Bertini-Sard theorem, we determine, up to birational equivalence, the separable proper morphisms of smooth algebraic varieties in characteristic two, whose fibres are non-smooth curves of arithmetic genus two. 
Alejandro Simarra Ca\~nate and Karl-Otto St\"ohr
math.AG