We will first briefly introduce our notational standards: Throughout this work, we will write general wavefunctions as |Ψ⟩ and determinants as |Φ⟩. The orbitals that build these determinants are indexed as i, j, k, . . . if occupied, as a, b, c, . . . if unoccupied (virtual) and as p, q, r . . . if they are either. Perturbation theoretical expressions are dressed with a superscript (n) if they refer to the n-th order contribution and possess a superscript [n] if they denote the full expression at n-th order, i. e.: