Markey Robinson Set of 4 Drawings

A fantastic group of 4 drawings by Markey Robinson.
The drawing done in pen are various landscape studies.
The drawing are are mounted and framed in two groups of two drawings.
The drawings are unsigned, with certification of authenticity from Markeys daughter Bernadette Robinson Muldowney, dated 2009 on the back of one piece.
The drawings are various sizes,
Group 1- 2 drawings, dark mount, drawings, 10 by 13.5 cm’s, overall size including frame , 23 by 43 cm’s.
Group 2- 2 drawings, light mount, drawings, 10 by 14.5 cm’s , overall size including frame , 22.5 by 42.5 cm’s.