For purposes of clarification and understanding of the terminology as it evolved over history, it suffices to end with the major publication that helped recognize the equivalence of the matrix mechanics of Born, Heisenberg, and Jordan 1925–1926 with the wave equation of Schrodinger in 1926. The collected and expanded works of John von Neumann showed that the two theories were mathematically equivalent, and it is this realization that is today understood as first quantization.