used 9-11, the study in green album, comprising 9, sixty-eight examples with several used on pieces or part entires and ten used on entires, 10, forty-nine examples with three used on entires and five used on part entires, 11, thirty-six examples with six used on entires and fourteen used on pieces or part entires, a number of differing states, re-entries, distinctive Crosses, etc.; mostly with three or four margins, condition a little mixed but many neatly cancelled and attractive included