%Ubhaya1977
\rhl{U}
\refJ Ubhaya,  V. A.;
Duality in approximation and conjugate cones in mormed linear spaces;
\JMAA; 58; 1977; 419--436;

%Ubhaya1979
\rhl{U}
\refJ Ubhaya,  V. A.;
An $O(n)$ algorithm for discrete $n$-point convex approximation with 
applications to continuous case;
\JMAA; 72; 1979; 338--354;

%Ubhaya1987
\rhl{U}
\refJ Ubhaya,  V. A.;
An $O(n)$ algorithm for least squares quasi-convex approximation;
\CMA; 14; 1987; 583--590;

%Ubhaya1990
% sonya
\rhl{U}
\refJ Ubhaya,  V. A.;
$L_p$ approximation by subsets of convex functions of several variables;
\JAT; 63; 1990; 144--155;

%Ueda1994
% larry
\rhl{U}
\refP Ueda, K.;
Multiplication as a general operation for splines;
\ChamonixIIa; 475--482;

%Ueda1997
% larry 10sep99
\rhl{U}
\rhl{U}
\refP Ueda, K.;
A sequence of B\'ezier curves generated by successive pedal-point
constructions;
\ChamonixIIIa; 427--434;

%Ueda2000
% larry 20apr00
\rhl{}
\refP Ueda, Kenji;
Central conics on parabolic Dupin cyclides;
\Stmalod; 399--406;

%UedaHarada1991a
\rhl{U}
\refQ Ueda,  K., Harada, T.;
Generalization of a family of Gregory surfaces;
(Scientific Visualization of Physical Phenomena),
N. M. Patrikalakis (ed.),
Springer-Verlag, (Berlin); 1991; 417--434;

%Uferev1981
\rhl{U}
\refJ Uferev,  V. S.;
Approximation locale par des fonctions
	 splines cubiques (Russian);
Z.  Vycisl.\  Mat.\  i Mat-Fiz.; 21; 1981;  5--10;

%Uhlig1992
% carl
\rhl{U}
\refJ Uhlig,  F.;
Are the coefficients of a polynomial well-conditioned functions of its roots?;
\NM; 61; 1992; 383--394;

%Ullal1975
\rhl{U}
\refJ Ullal,  A. N.;
Splinefunktionen und ihre Anwendungen;
Melliand.\  Textilber.\  Int.; 56; 1975;	488--492;

%UlrichGWatsonLT1987
% author 03dec99
\rhl{U}
\refJ Ulrich, G.,  Watson, L. T.;
A method for computer generation of variates from
   arbitrary continuous distributions;
\SJSSC; 8; 1987; 185--197;

%UlrichWatsonLT1994
% author 03dec99
\rhl{U}
\refJ Ulrich,  G., Watson, L. T.;
Positivity conditions for quartic polynomials;
\SJSC; 15; 1994; 528--544;

%Uluchev1989
% shayne
\rhl{U}
\refJ Uluchev,  R. K.;
B-splines with Birkhoff knots, applications in the approximations and
shape preserving interpolation;
Math.\ Balkanica; 3; 1989; 225--239;

%Uluchev1991
\rhl{U}
\refP Uluchev,  R.;
Geometric Birkhoff interpolation with parametric quadratic splines;
\VarnaVI; submitted;

%Uluchev1991b
% . 19nov95
\rhl{U}
\refP Uluchev, R.;
Smoothest interpolation with free nodes in $W_p^r$;
\Progress; 787--806;

%UmarWuJStrayerBottcher93;
% . 04mar10
\rhl{}
\refJ Umar, A. S., Wu, J., Strayer, M. R., Bottcher, C.;
The basis-spline collocation method for the lattice solution of boundary
   value problems;
J. Comput.\ Phys.; 93; 1991; 426--448;

%UmarWuStrayerBottcher1991
% larry
\rhl{UWSB}
\refJ Umar,  A. S., Wu, J., Strayer, M. R., Bottcher, C.;
Basis-spline collocation method for the lattice solution of boundary value 
   problems;
\JCP; 93; 1991; 426--448;

%Unser1990
\rhl{U}
\refQ Unser,  M.;
Recursive filters for fast B-spline interpolation and compression of digital
images;
(Proceedings on Medical Imaging IV: Image Capture and Display),
xxx (ed.), xxx (xxx); 1990; 1--11;

%Unser1999
% carlrefs 20nov03
\rhl{}
\refJ Unser, Michael;
Splines: A perfect fit for signal and image processing;
IEEE Signal Processing Mag.; Nov; 1999; 22--38;

%UnserAldroubiEden1991
\rhl{U}
\refJ Unser,  M., Aldroubi, A., Eden, M.;
Fast B-spline transforms for continuous image representation and interpolation;
\ITPAMI; 13; 1991; 277--285;

%UnserBlu2000
% carl 04mar10
\rhl{}
\refJ Unser, M., Blu, T.;
Fractional splines and wavelets;
\SR; 42(1); 2000; 43--67;

%Usmani1987
% . 20nov03
\rhl{U}
\refJ Usmani, Riaz A.;
On quadratic spline interpolation;
\BIT; 27; 1987; 615--622;
% Laszlo03 claims that the coefficient for the h^6 term in (3.7) should be
% -(31/20160)

%Usmani1996a
% carl 5dec96
\rhl{U}
\refJ Usmani, Riaz A.;
Error bounds for periodic quartic spline interpolation;
\ATA; 12(3); 1996; 1--9;
% uniform knots, claims better results than for corresponding quintic case

%UsmaniSakai1982
\rhl{U}
\refJ Usmani,  R. A., Sakai, M.;
A note on quadratic spline interpolation at midpoints;
\BIT; 22; 1982;  261--267;

%UsmaniSakai1989a
% author 5dec96
\rhl{U}
\refJ Usmani, Riaz A., Sakai, M.;
A connection between quartic spline solution and Noumerov solution of a
   boundary value problem;
Intern.\ J. Computer Math.; 26; 1989; 263--273;

%UstumerFerrariSankarSilbermann1988
\rhl{U}
\refR \"Ust\"umer,  K. F., Ferrari, L. A., Sankar, P. V., Silbermann, M. J.;
An efficient method for the computation of discrete splines;
Univ.\ of California; 1988;

%Utreras1978
\rhl{U}
\refR Utreras, F.;
Utilisation des programmes de calcul du parametre d'ajustement dans le
lissage par fonctions spline;
Grenoble; 1978;

%Utreras1979a
\rhl{U}
% mr
\refQ Utreras,  F. I.;
Cross validation techniques for smoothing spline functions in one or
   two dimensions;
(Smoothing Techniques for Curve Estimation: Lecture Notes in Math.~757),
M. Rosenblatt and Th.\ Gasser (eds.), Springer Verlag (Berlin); 1979; 196--232;

%Utreras1979b
\rhl{U}
\refD Utreras,  F.;
Utilisation de la m\'ethod de validation crois\'ee pour le
   lissage par fonctions spline \`a une ou deux variables;
Univ.\ Grenoble; 1979;

%Utreras1980
% larry
\rhl{U}
\refJ Utreras,  F.;
Sur la choix du parametre d'ajustement
   dans le lissage par fonctions spline;
\NM; 34; 1980;	15--28;

%Utreras1980b
\rhl{U}
\refJ Utreras, F.;
On the eigenvalue problem associated with cubic splines: the arbitrarily
spaced knot case;
SIGMA; 6; 1980; 23--39;

%Utreras1980c
\rhl{U}
\refR Utreras, F.;
A package for smoothing noisy data with splines;
Univ.\ Santiago, Chile; 1980;

%Utreras1981
% larry
\rhl{U}
\refJ Utreras,  F.;
On computing robust splines and applications;
\SJSSC; 2; 1981; 153--163;

%Utreras1981b
% larry
\rhl{U}
\refJ Utreras,  F.;
Optimal smoothing of noisy data using spline functions;
\SJSSC; 2; 1981;  349--362;

%Utreras1982
% sonya
\rhl{U}
\refJ Utreras,  F.;
Convergence rates for monotone cubic spline interpolation;
\JAT; 36; 1982; 86--90;

%Utreras1982b
\rhl{U}
\refR Utreras, F.;
Obtention des ordres de convergence des fonctions spline avec
contraintes;
xx; 1982;

%Utreras1983a
% larry 23may95
\rhl{U}
\refJ Utreras, Florencio;
Natural spline functions, their associated eigenvalue problem;
\NM; 42; 1983;  107--117;
% smoothing spline. shows that eigenstructure of (univariate) smoothing spline 
% problem for uniform data mesh is closely related to the eigenstructure of a
% simple ODE.

%Utreras1984
\rhl{U}
\refR Utreras, F.;
Two-dimensional splines;
xx; 1984;

%Utreras1985a
% larry
\rhl{U}
\refJ Utreras,  F. I.;
Positive thin plate splines;
\ATA; 1; 1985; 77--108;

%Utreras1985b
% mr 21jan02
\rhl{U}
\refJ Utreras, F.;
Smoothing noisy data under monotonicity constraints:\ Existence,
   characterization and convergence rates;
% CAT \# 83: 1985:
\NM; 47(4); 1985; 611--625;
% MR 87g:65022

%Utreras1986
% larry
\rhl{U}
\refP Utreras,  F. I.;
Positive smoothing splines;
\TexasV; 603--606;

%Utreras1987
\rhl{U}
\refP Utreras,  F. I.;
Constrained surface construction;
\Chile; 233--254;

%Utreras1988a
% sherm, pagination update
\rhl{U}
\refJ Utreras,  F. I.;
On generalized cross-validation for multivariate
smoothing spline functions;
\SJSSC; 8(4); 1988; 630--643;

%Utreras1988b
\rhl{U}
\refJ Utreras, F. I.;
Convergence rates for multivariate smoothing spline functions;
% CAT \#75, 1985,
\JAT; 52; 1988; 1--27;

%Utreras1988c
% . 02feb01
\rhl{U} 
\refP Utreras, F. I.;
The variational approach to shape preservation;
\ChamonixI; 461--476;

%Utreras1988d
% mr 21jan02
\rhl{U}
\refJ Utreras, F.;
Boundary effects on convergence rates for Tikhonov regularization;
\JAT; 54(3); 1988; 235--249;

%Utreras1992
% mr 21jan02
\rhl{}
\refP Utreras, Florencio I.;
Recent results on multivariate smoothing splines;
\Duisburg; 299--312;
% MR92j:41024