  Quasimodules for vertex algebras are generalizations of modules for vertex
algebras. These new objects arise from a generalization of locality for fields.
Quasimodules tie together module theory and twisted module theory, and both
twisted and untwisted modules feature Poincare-Birkhoff-Witt-like spanning
sets. This paper generalizes these spanning set results to quasimodules for
certain Mobius vertex algebras. In particular this paper presents two spanning
sets, one featuring a difference-zero ordering restriction on modes and another
featuring a difference-one condition.
