More cover scans, courtesy of yours truly:
[CLICK IMAGES TO ENLARGE]
ABOVE: Clifford D. Simak, Enchanted Pilgrimage (NY: Berkley, 1975), Z2987, with cover art by Paul Lehr.
ABOVE: Stephen Tall, The Ramsgate Paradox (NY: Berkley, c1976), Z3186, with cover art by Paul Lehr.
ABOVE: Anders Bodelsen, Freezing Down (NY: Berkley, 1972), S2186, with cover art by Paul Lehr.
ABOVE: Harry Harrison and Brian Aldiss, eds., Best SF 73 (NY: Berkley, 1974), with cover art by Paul Lehr.
The art on the cover of Freezing Down is uncredited, and no signature is visible, but I’m going to go ahead and attribute it to Paul Lehr. If you know better, you are welcome to post a comment and set the record straight.