“I.O.U.S.A.” (IOU + USA) was printed in an income tax poem by an anonymous author that appeared in several newspapers since 1952:
 
“Income tax is almost due,
And this makes me, today,
An honest charter member of
I.O.U.S.A.”
 
 
23 February 1952, Logan (OH) Daily News, pg. 8, col. 2:
Income tax is almost due,
And this makes me, today,
An honest charter member of
I.O.U.S.A.
 
21 December 1952, Atchison (KS) Daily Globe, “Plain Talk” by the Jayhawk, pg. 10, col. 2:
Since we just got our quarterly query from the Internal Revenue office, we find this jungle fits the season well:
   
Income tax is almost due,
And this makes me, today,
An honest charter member of
I.O.U.S.A.
   
12 February 1953, Palatine (IL) Enterprise, “Northwest Achers” by Betty Blaine, pg. 3, col. 3:
“Income tax is almost due,
And this makes me, today,
An honest charter member of
I.O.U.S.A.”
 
6 March 1955, New York (NY) Times, “Tax Bites Man: With tax time last approaching, a selection of bleats and cries on the subject is pertinent” compiled by Frances Rodman, Magazine, pg. 58, col. 2:
“Income tax is almost due
And this makes me today
An honest charter member of
I.O.U.S.A.”—Anon.
 
2 April 1955, Anderson (IN) Herald, “Folklore” by William Wade, pg. 4, col. 4:
An anonymous rhymester has written the following about a problem bothering most people at this time:
 
Income tax is almost due and this makes me today
An honest charter member of I.O.U.S.A.
 
25 March 1957, Blytheville (AR) Courier News, pg. 6, col. 2:
As a counter attack, we propose a little anthem which might be called I Want My Woe to Show:
 
Income tax is almost due
And this makes me today
A wretched charter member
I. O. U. S. A.
Should I grin and bear it?
Should I hip hooray?
Not as a charter member of
I. O. U. S. A.
(...)
—- Charlotte (N.C.) News.