Dilation Effect Douglas R. Mason PB 1st Ballantine (1971)

Horizon Alpha Douglas R. Mason PB 1st Ballantine (1971)

Eight Against Utopia Douglas R. Mason PB 1st Paperback Library (1967)

Satellite 54 Zero Douglas R. Mason PB 1st Ballantine (1971)

Moons Of Triopus John Rankine aka Douglas R Mason PB 1st Paperback Library 1969

Ring of Violence Douglas R. Mason PB 1st Avon (1969)

Dilation Effect by Douglas R. Mason - pb

VTG 1963 BALLANTINE EDGAR RICE BURROUGHS A Princess of Mars F-701 PB Book 1st Ed