U.S. Naval Observatory, Washington, DC 20392-5100. Report for the period 1 Jul 1989 - 30 Jun 1990.

U.S. Naval Observatory, Washington, DC 20392-5100. Report for the period 1 Jul 1990 - 30 Jun 1991.

U.S. Naval Observatory, Washington, DC 20392-5100. Report for the period 1 Jul 1991 - 30 Jun 1992.

U.S. Naval Observatory, Washington, DC 20392-5420. Report for the period 1 Jul 1992 - 30 Jun 1993.

U.S. Naval Observatory, Washington, DC 20392-5420. Report for the period 1 Jul 1993 - 30 Jun 1994.

U.S. Naval Observatory, Washington, DC 20392-5420. Report for the period Jul 1994 - Jun 1995.

U.S. Naval Observatory, Washington, DC 20392-5420. Report for the period Jul 1996 - Jun 1997.

U.S. Naval Observatory, Washington, DC 20392-5420. Report for the period Jul 1997 - Jun 1998.

U.S. Space and Planetary Science - a 7-YEAR Plan

U.S., European ALMA Partners Award Prototype Antenna Contracts

U.S.-Canadian Partnership in Radio Astronomy Valuable for Science, NRAO Director Says

U.S.-India Space Partnership: The Jewel in the Crown

U.S.-U.S.S.R. space cooperation

U.S.N. Observatory Washington. Observations of Euphrosyne, made with the Filar-Micrometer of the Equatorial by J. Ferguson

U.S.NAVAL Observatory

U1(prime) dark matter and R-parity violation

U93.174 - A new interstellar line with quadrupole hyperfine splitting

UAD Camp at Kurescek. (Slovenian Title: Tabod UAD na Kurescku)

UAI e mass media. L'informazione sui maggiori eventi astronomici: il contributo degli astrofili

Ual - Undefined Acronym List