This issue has variants.
The on-sale date is the publication date reported in the U. S. Copyright Office filing.
An earlier indexer provided an on-sale date of May 11. No citation was given, although another indexer notes that it matches a listing in the fanzine The Comics Reader.
The Madbomb Part 8.
Letters from Bill Dickenson, Mark R. Kausch, Larry Twiss, Mike Underwood, Doug Zimmerman