Technical Art examination of Picasso has been more numerous than other 20th century painters. There are reliable resources on the internet from renowned institutions, such as the Art Institute Chicago
, MoMA  and V&A . Other information on the painting materials Picasso used thoughtout his life are found in scientific journals [4-7] and conservation publications [8, 9].
Online References Art Institute Chicago “Revealing Picasso Conservation Project”. A nice introductory-level technical examination of the “Old guitarist”.  MoMA “Les Demoiselles d’Avignon Conserving a modern masterpiece”. Imaging and pigments analysis.  Fotini Koussiaki “My Picture Is A Sum Of Destructions, Pablo Picasso (1881-1973)” Victoria and Albert Museum, Conservation Journal, Spring 2000 Issue 34. Stylistic and palette information.
References F. Casadio, A. Bezúr, I. Fiedler, K. Muir, T. Trad, S. Maccagnola “Pablo Picasso to Jasper Johns: a Raman study of cobalt-based synthetic inorganic pigments” J. Raman Spectrosc. 2012, 43, 1761 – 1771.  F. Cappitelli, F. Koussiaki “THM-GCMS and FTIR for the investigation of paints in Picasso’s Still Life, Weeping Woman and Nude Woman in a Red Armchair from the Tate Collection, London” J. Anal. Appl. Pyrolysis 75 (2006) 200–204.  J. Delaney, J. G. Zeibel, M. Thoury, R. Littleton, M. Palmer, K. M. Morales, E. Rene De La Rie, A. Hoenigswald “Visible and Infrared Imaging Spectroscopy of Picasso’s Harlequin Musician: Mapping and Identiﬁcation of Artist Materials in Situ” Applied Spectroscopy, V.64, 6, pp 584-594, 2010.  F. Casadio, V. Rose “High-resolution ﬂuorescence mapping of impurities in historical zinc oxide pigments: hard X-ray nanoprobe applications to the paints of Pablo Picasso” Applied Physics A, published online: 24 January 2013.  Delbourgo, S. “Etude de la Matière Picturale de Pablo Picasso”. Ottawa: Comité pour la conservation de l’ICOM 6éme Réunion triennale, 1981.  A. Hoenigswald “Works in Progress: Pablo Picasso’s hidden images” in Picasso, the Early Years: 1892-1906 , ed. Marilyn McCully, Washington, D. C.: National Gallery of Art; 1997.