Gennadii V. Demidenko & Stanislav V. Upsenskii 
Partial Differential Equations And Systems Not Solvable With Respect To The Highest-Order Derivative 

Offering in-depth analyses of current theories and approaches related to Sobolev-type equations and systems, this reference is the first to introduce a classification of equations and systems not solvable with respect to the highest order derivative, and it studies boundary value problems for these classes of equations. Presenting 2200 equations, t