This is Giant Superman 20, published by Mimosa (SA Magazine Co) +/- 1963-1964.
It reprints the cover and both stories from DC Comics' Action Comics 294 (1962):
"The Kryptonite Killer"
Supergirl: "The Mutiny of Super-Horse"
Also reprinted is this story from DC Comics' Adventure Comics 249 (1958):
"The Stolen Superboy Cape"
Also reprinted is this story from DC Comics' Adveture Comics 248 (1958):
Green Arrow: "The World's Most Dangerous Arrow"
48pages, glossy colour cover, black and white newsprint interior.
Here is the cover of issue 20 and DC Comics' original cover: