C. de Cedillo, Toledo en el siglo XVI , Madrid, 1901, note 121.
M.B. Cossio, El Greco , II, Madrid, 1908, pp. 433-436, 602, no. 127, as 'San Ignacio de Loyola'.
A.F. Calvert and C.G. Hartley, El Greco: An account of his life and works , New York and London, 1909, p. 145, pl. 27, as 'Portrait of a Student'.
A.L. Mayer, El Greco , Munich, 1911, pp. 64, 89, pl. 25, as 'Der hl. Luis Gonzaga'.
P. Lafond, El Greco , Paris, 1913, p. 102, as 'Saint Ignace de Loyola'.
H. Kehrer, Die Kunst des Greco , Munich, 1914, p.54, as 'Luis Gonzaga'.
E. du Gue Trapier, El Greco, New York, 1925, p. 142, as ‘Portrait San Ignacio de Loyola also known as Luis de Gonzaga'.
A.L. Mayer, Domenico Theotocopuli, El Greco , Munich, 1926, p. 52, no. 328 (324), pl. LXXIII, as ‘Bildnis des hl. Luis Gonzaga (?)'.
E.H. del Villar, El Greco en España , Madrid, 1928, pp. 152-153, pl. XXXVI, fig. 69, as ‘un jesuíta joven [?]'.
F. Gray Griswold, El Greco , printed privately, 1929, no. XXX, as ‘Saint Ignacio Loyola'.
M. Utrillo, Domenikos Theotokopoulos, El Greco , Barcelona, 1930, pl. 3, as ‘Un estudiante [El Greco?]'.
A.L. Mayer, El Greco , Berlin, 1931, pp. 98-99 and 172, pl. 65, as ‘Saint Aloysius Gonzaga [?]'.
M. Seuphor, Greco, Considerations sur sa Vie et sur quelques unes de ses oeuvres , Paris, 1931, p. 16, as ‘Saint Louis de Gonzaga'.
T. Borenius, ‘The Stefan von Auspitz Collection, Review of Exhibition at Agnew', Burlington Magazine, LXI, 1932, pp. 287-288, pl. II-B, as 'Saint Aloysius Gonzaga'.
M. Legendre and A. Hartmann , Domenico Theotocopouli, dit El Greco , Paris, 1937, p. 41, illustrated, as 'Saint Luis de Gonzaga'.
L. Goldscheider, El Greco , London, 1938, n.p., fig. 108.
W.G. Constable, Annual Report for the Year (Museum of Fine Arts, Boston) , Boston, LXIV, Boston, 1939, p. 45.
L. Goldscheider, El Greco , London, 1949, n.p., pl. 64.
G. Ludwig, El Greco , 1949, pl. 64.
J. Camón Aznar, Domenico Greco , I, Madrid, 1950, pp. 1096-1098, fig. 856 (showing the hand above the book in its original position after cleaning) and fig. 857 (showing the overpainted hand below the book); II, p. 1393, nos. 726 and 727 (as ‘Portrait of a young master'; Mayer speculates as to whether nos. 726 and 727 might be two different paintings).
V. Cepari, San Luis Gonzaga (life of the saint) , Madrid, 1953, pp. 35-36 and 48-49.
H. Soehner, ‘Greco in Spanien: Teil I: Grecos Stilentwicklung in Spanie', Munchner Jahrbuch der bildenden Kunst , III, 1957, p. 141.
H.E. Wethey, El Greco and his School , I, Princeton, 1962, fig. 246; II, pp. 108-109, no. 195.
H.E. Wethey, El Greco y su escuela , I, Madrid, 1967, p. 141, no. 195, fig. 227, as 'Saint Aloysius Gonzaga (so called)'.
T. Frati and G. Mazini , L'opera completa del Greco , Milan, 1969, p. 99, no. 45, illustrated.
J. Camón Aznar, Domenico Greco , Madrid, 1970, p. 1097 and 1099, figs. 940 and 941.
T. Frati, Tout l'oeuvre peint de Greco , Paris, 1971, p. 99, no. 45, 'San Luigi Gonzaga (?)'.
M.B. Cossio, El Greco , Barcelona, 1972, pp. 260-262, 395, no. 365, 'San Ignacio de Loyola'.
J. Giudiol, Domenikos Theotokopoulos, El Greco 1541-1614 , London, 1973, pp. 112, 344, no. 72, fig. 98, 'Saint Aloysius Gonzaga(?)'.
M. Paganella, San Luigi Gonzaga, un ritratto in piedi , Milan, 1991, illustrated on the cover.
J. Álvarez Lopera, El Greco: la obra esencial , Spain, 1993, p. 282, no. 84, as 'Retrato de un estudiante (San Luis Gonzaga)'.
B. Wismer and M. Scholz-Hänsel, El Greco and Modernism , exhibition catalogue, Ostfildern, 2012, p. 343.