Add a reference for USYMQR

src/usymqr.jl

@@ -6,6 +6,10 @@
 # Two Conjugate-Gradient-Type Methods for Unsymmetric Linear Equations.
 # SIAM Journal on Numerical Analysis, 25(4), pp. 927--940, 1988.
 #
+# L. Reichel and Q. Ye
+# A generalized LSQR algorithm.
+# Numerical Linear Algebra with Applications, 15(7), pp. 643--660, 2008.
+#
 # A. Buttari, D. Orban, D. Ruiz and D. Titley-Peloquin
 # A tridiagonalization method for symmetric saddle-point and quasi-definite systems.
 # SIAM Journal on Scientific Computing, 41(5), pp. 409--432, 2019.
@@ -73,6 +77,7 @@ USYMQR finds the minimum-norm solution if problems are inconsistent.
 #### References
 
 * M. A. Saunders, H. D. Simon, and E. L. Yip, [*Two Conjugate-Gradient-Type Methods for Unsymmetric Linear Equations*](https://doi.org/10.1137/0725052), SIAM Journal on Numerical Analysis, 25(4), pp. 927--940, 1988.
+* L. Reichel and Q. Ye, [*A generalized LSQR algorithm*](https://doi.org/10.1002/nla.611), Numerical Linear Algebra with Applications, 15(7), pp. 643--660, 2008.
 * A. Buttari, D. Orban, D. Ruiz and D. Titley-Peloquin, [*A tridiagonalization method for symmetric saddle-point and quasi-definite systems*](https://doi.org/10.1137/18M1194900), SIAM Journal on Scientific Computing, 41(5), pp. 409--432, 2019.
 * A. Montoison and D. Orban, [*BiLQ: An Iterative Method for Nonsymmetric Linear Systems with a Quasi-Minimum Error Property*](https://doi.org/10.1137/19M1290991), SIAM Journal on Matrix Analysis and Applications, 41(3), pp. 1145--1166, 2020.
 """