UGANDA
1984 ##427-430, ss#431
1989 ##703-716 (all were reissued with different denominations in 1990-92 as ##826-839, +##839A-839C)
1994 ##1222-1229, ss##1230-1231
1996 1sheet of 12(a.-l.) #1424, ss##1425-1426
2000 ##1627-1632, ss#1633
2000 ##1645-1648, sheets of 8 ##1649-1651, ss##1652-1653
2002 1 stamp out of sheet of 6 - sheet #1776 (itself 1 out of 4 in set)(could be more stamps or sheets in this set)
URUGUAY
1978 1stamp out of set #1007 (sheet of 4); also 1007a exists
1995 1 sheet of 4(a.-d.) #1576
1998 ##1731-1732; also exist as a pair #1732a.
2003 1 Block of 4 #2000
USA
1977 ##1712-1715; also exist as block of 4 #1715a and imperforated block of 4 #1715b
1987 3stamps out of set?
1996 1stamp out of set #3105
1999 (2 stamps out of pane of 20 #3351)
2000 (1stamp out of pane of 10 )

UZBEKISTAN
1992 1stamp
1995 ##80-86, ss#87
UNITED ARAB EMIRATES
1997 #549 (3 additional stamps were issued but Scott didn't examine them yet)
1999 (1 stamp out of set #634; could be more stamps)
UNION ISLAND
1985 ##194-201(se-tenant by two of the same denomination)
UDMURTIA
???? strip of 4
???? sheet of 4