[1] A. Ben-Israel and T. N. E. Greville, Generalized Inverses, Theory and Applications, 2nd ed., CMS Books in Mathematics/Ouvrages de Math�matiques de la SMC, 15, Springer-Verlag, New York, 2003 [an updated bibliography on generalized inverses may be accessed at http://www.math.technion.ac.il/iic/benisrael.html].

[2] D. Bini, M. Capovani and O. Menchi, Metodi Numerici per l�Algebra Lineare, Zanichelli, Bologna, 1993.

[3] S. L. Campbell and C. D. Meyer, Jr., Generalized Inverses of Linear Transformations, Dover Publications, New York, 1991.

[4] N. Carter, Visual group theory, Classroom Resource Materials Series, Mathematical Association of America, Washington, DC, 2009.

[5] R. E. Cline, Elements of the theory of generalized inverses for matrices, UMAP modules and monographs in undergraduate mathematics and its applications project, The UMAP Expository Monograph Series, EDC/UMAP, Newton, Mass., 1979.

[6] C. Costa and R. Ser�dio, A footnote on quaternion block-tridiagonal systems, orthogonal polynomials: numerical and symbolic algorithms, Legan�s, 1998, Electron. Trans. Numer. Anal. 9 (1999), 53-55.

[7] C. Costa, F. Martins, R. Ser�dio, P. Tadeu, M. A. Facas Vicente and J. Vit�ria, Conjugacy and geometry I - foot of the perpendicular, distance and Gram determinant, Far East J. Math. Edu. 3(3) (2009), 235-262.

[8] R. Cramer, E. Kiltz and C. Padr�, A note on secure computation of the Moore-Penrose pseudoinverse and its application to secure linear algebra, Advances in Cryptology �CRYPTO 2007, 613-630, Lecture Notes in Comput. Sci., 4622, Springer, Berlin, 2007.

[9] H. P. Decell, Jr., An application of the Cayley-Hamilton theorem to generalized matrix inversion, SIAM Rev. 7 (1965), 526-528.

[10] F. Deutsch, Best Approximation in Inner Product Spaces, Springer, New York, 2001.

[11] A. M. Dupr� and S. Kass, Distance and parallelism between flats in Linear Algebra Appl. 171 (1992), 99-107.

[12] B. Eckmann, Stetige L�sungen linearer Gleichungssysteme, Comment. Math. Helv. 15 (1943), 318-339 (in German).

[13] T. N. E. Greville, The Souriau-Frame algorithm and the Drazin pseudoinverse, Linear Algebra Appl. 6 (1973), 205-208.

[14] J. Gross and G. Trenkler, On the least squares distance between affine subspaces, Linear Algebra Appl. 237/238 (1996), 269-276.

[15] C. C. MacDuffee, The Theory of Matrices, Chelsea, New York, 1956 [There are various Chelsea reprints of the first edition (1933) of this book, Julius Springer, Berlin].

[16] A. Martin�n, Distance to the intersection of two sets, Bull. Austral. Math. Soc. 70(2) (2004), 329-341.

[17] F. Martins, E. Pereira and J. Vit�ria, Block compound matrices and differential matrix equations, Far East J. Appl. Math. 17(2) (2004), 221-242.

[18] W. S. Massey, Cross products of vectors in higher-dimensional Euclidean spaces, Amer. Math. Monthly 90(10) (1983), 697-701.

[19] Z. A. Melzak, Companion to Concrete Mathematics - Two Volumes Bound as One, Dover Publications, New York, 2007 [Volume I published in 1973 and Volume II published in 1976 by J. Wiley].

[20] C. D. Meyer, Matrix Analysis and Applied Linear Algebra, SIAM, Philadelphia, 2000.

[21] K. P. S. Bhaskara Rao, The Theory of Generalized Inverses over Commutative Rings, Taylor & Francis, London, New York, 2002.

[22] J. Vit�ria, Singular and nonsingularizable higher-order differential matrix equations, pages 686-691, Report of International Conference on Linear Algebra and Applications, Universidad Politecnica de Valencia/Spain, 28-30 September 1987, R. Bru and J. Vit�ria, editors, Linear Algebra Appl. 121 (1989), 537-710.

[23] Guorong Wang, An application of the block Cayley-Hamilton theorem, J. Shangai Normal Univ. 20 (1991), 1-10 (in Chinese) [English translation by Yulin Zhang].

[24] Guorong Wang, Yimin Wei and Sanzheng Qiao, Generalized Inverses: Theory and Computations, Science Press, Beijing, New York, 2004.

[25] S. Wolfram, The Mathematica Book, 4th ed., Wolfram Media, Inc., Champaign, IL, Cambridge University Press, Cambridge, 1999.