in Showcase Presents Hawkman (DC, 2007 series) #2 ([July] 2008)house ad for Secret Six (DC, 1968 series) #2 and The Brave and the Bold (DC, 1955 series) #78
in Showcase Presents Hawkman (DC, 2007 series) #2 ([July] 2008)
from Real Fact Comics (DC, 1946 series) #1 (March-April 1946)house ad for Superman (DC, 1939 series) #207 [80 Page Giant #G-48], on sale April 9
listing of DC comics on sale in late April, 1968; page includes cover art from Adventure Comics (DC, 1938 series) #369 and Detective Comics (DC, 1927 series) #376
hint submitted by Joe Gregory of Greensboro, North Carolina