There are 2 titles associated with this person.

Stevens , G.B. (1818). Llewellen, or the vale of phlinlimmon: a novel. in two volumes. Philadelphia: M. Carey and Son [126 Chestnut Street]
Stevens , G.B. (1818). Llewellen, or, the vale of phlinlimmon: a novel. in three volumes. Edinburgh: Macredie, Skelly, and Co. Thomas and George Underwood.