T. M. Callaghan and K. P. Wilhelm, “A Review of Ageing and an Examination of Clinical Methods in the Assessment of Ageing Skin. Part 2: Clinical Perspectives and Clinical Methods in the Evaluation of Ageing Skin,” International Journal of Cosmetic Science, Vol. 30, No. 5, 2008, pp. 323-332.
 D. A. Gunn, H. Rexbye, C. E. Griffiths, P. G. Murray, A. Fereday, S. D. Catt, C. C. Tomlin, B. H. Strongitharm, D. I. Perrett, M. Catt, A. E. Mayes, A. G. Messenger, M. R. Green, F. van der Ouderaa, J. W. Vaupel and K. Christensen, “Why Some Women Look Young for Their Age,” PLoS One, Vol. 4, No. 12, 2009, Article ID: e8021. http://dx.doi.org/10.1371/journal.pone.0008021
 M. A. Farage, K. W. Miller, P. Elsner and H. I. Maibach, “Intrinsic and Extrinsic Factors in Skin Ageing: A Review,” International Journal of Cosmetic Science, Vol. 30, No. 2, 2008, pp. 87-95.
 L. Yin, A. Morita and T. Tsuji, “Skin Aging Induced by Ultraviolet Exposure and Tobacco Smoking: Evidence from Epidemiological and Molecular Studies,” Photodermatology, Photoimmunology & Photomedicine, Vol. 17, No. 4, 2001, pp. 178-183. http://dx.doi.org/10.1034/j.1600-0781.2001.170 407.x
 W. C. Leung and I. Harvey, “Is Skin Ageing in the Elderly Caused by Sun Exposure or Smoking?” British Journal of Dermatology, Vol. 147, No. 6, 2002, pp. 1187-1191. http://dx.doi.org/10.1046/ j.1365-2133.2002.04991.x
 S. Cho, M. H. Shin, Y. K. Kim, J. E. Seo, Y. M. Lee, C. H. Park and J. H. Chung, “Effects of Infrared Radiation and Heat on Human Skin Aging in Vivo,” Journal of Investigative Dermatology Symposium Proceedings, Vol. 14, No. 1, 2009, pp. 15-19. http://dx.doi.org/10.1038/jidsymp.2009.7
 V. L. Ernster, D. Grady, R. Miike, D. Black, J. Selby and K. Kerlikowske, “Facial wrinkling in men and women, by smoking status,” Am J Public Health. Vol. 85, No. 1, 1995, pp. 78-82.
 J. M. Waller and H. I. Maibach, “Age and Skin Structure and Function, a Quantitative Approach (I): Blood Flow, pH, Thickness, and Ultrasound Echogenicity,” Skin Research and Technology, Vol. 11, No. 4, 2005, pp. 221-235. http://dx.doi.org/10.1111/j.0909-725X.2005.00151.x
 N. Krueger, S. Luebberding, M. Oltmer, M. Streker and M. Kerscher, “Age-Related Changes in Skin Mechanical Properties: A Quantitative Evaluation of 120 Female Subjects,” Skin Research and Technology, Vol. 17, No. 2, 2011, pp. 141-148. http://dx.doi.org/10.1111/j.1600-0846.2010.00486.x
 T. Fujimura, K. Haketa, M. Hotta and T. Kitahara, “Loss of Skin Elasticity Precedes to Rapid Increase of Wrinkle Levels,” Journal of Dermatological Science, Vol. 47, No. 3, 2007, pp. 233-239.
 G. J. Fisher, J. Varani and J. J. Voorhees, “Looking Older: Fibroblast Collapse and Therapeutic Implications,” Archives of Dermatology, Vol. 144, No. 5, 2008, pp. 666-672.
 K. Tsukahara, T. Fujimura, Y. Yoshida, T. Kitahara, M. Hotta, S. Moriwaki, P. S. Witt, F. A. Simion and Y. Takema, “Comparison of Age-Related Changes in Wrinkling and Sagging of the Skin in Caucasian Females and in Japanese Females,” Journal of Cosmetic Science, Vol. 55, No. 4, 2004, pp. 351-371.
 S. Nouveau-Richard, Z. Yang, S. Mac-Mary, L. Li, P. Bastien, I. Tardy, C. Bouillon, P. Humbert and O. de Lacharrière, “Skin Ageing: A Comparison between Chinese and European Populations: A Pilot Study,” Journal of Dermatological Science, Vol. 40, No. 3, 2005, pp. 187-193.
 K. Tsukahara, K. Sugata, O. Osanai, A. Ohuchi, Y. Miyauchi, M. Takizawa, M. Hotta and T. Kitahara, “Comparison of Age-Related Changes in Facial Wrinkles and Sagging in the Skin of Japanese, Chinese and Thai Women,” Journal of Dermatological Science, Vol. 47, No. 1, 2007, pp. 19-28. http://dx.doi.org/10.1016/j.jdermsci.2007.03.007
 G. G. Hillebrand, K. Miyamoto, B. Schnell, M. Ichihashi, R. Shinkura and S. Akiba, “Quantitative Evaluation of Skin Condition in an Epidemiological Survey of Females Living in Northern versus Southern Japan,” Journal of Dermatological Science, Vol. 27, No. S1, 2001, pp. S42-S52.
 K. Asakura, Y. Nishiwaki, A. Milojevic, T. Michikawa, Y. Kikuchi, M. Nakano, S. Iwasawa, G. Hillebrand, K. Miyamoto, M. Ono, Y. Kinjo, S. Akiba and T. Takebayashi, “Lifestyle Factors and Visible Skin Aging in a Population of Japanese Elders,” Journal of Epidemiology, Vol. 19, No. 5, 2009, pp. 251-259. http://dx.doi.org/10.2188/jea.JE20090031
 H. Qiu, X. Long, J. C. Ye, J. Hou, J. Senee, A. Laurent, R. Bazin, F. Flament, A. Adam, J. Coutet and B. Piot, “Influence of Season on Some Skin Properties: Winter vs. Summer, as Experienced by 354 Shanghaiese Women of Various Ages,” International Journal of Cosmetic Science, Vol. 33, No. 4, 2011, pp. 377-383. http://dx.doi.org/10.1111/j.1468-2494.2011.00639.x
 G. Imokawa, “Recent Advances in Characterizing Biological Mechanisms Underlying UV-Induced Wrinkles: A Pivotal Role of Fibrobrast-Derived Elastase,” Archives of Dermatological Research, Vol. 300, No. S1, 2008, pp. S7-S20. http://dx.doi.org/10.1007/s00403-007-0798-x
 S. Imayama and I. M. Braverman, “A Hypothetical Explanation for the Aging of Skin. Chronologic Alteration of the Three-Dimensional Arrangement of Collagen and Elastic Fibers in Connective Tissue,” American Journal of Pathology, Vol. 134, No. 5, 1989, pp. 1019-1025.