There are 2 titles associated with this firm.

Richardson, Caroline E. Poems. By Mrs. G. G. Richardson, Dumfries. Edinburgh: Robert Cadell and Co. [41 St. Andrew Street], Simpkin, Marshall and Co., John Sinclair, 1828.
Richardson, Caroline E. Poems. By Mrs. G. G. Richardson, Dumfries. Edinburgh: Robert Cadell and Co. [41 St. Andrew Street], Simpkin, Marshall and Co., John Sinclair, 1829.