http://www.historyofinformation.com/expanded.php?id=2495

  Face Recognition by Humans: Nineteen Results Researchers Should Know About http://web.mit.edu/bcs/sinha/papers/19results_sinha_etal.pdf

  http://www.vision.caltech.edu/html-files/EE148-2005-Spring/pprs/viola04ijcv.pdf

  http://www.cmap.polytechnique.fr/~mallat/papiers/MallatTheory89.pdf (V.A)

  http://www.whydomath.org/node/wavlets/hwt.html

  http://ieeexplore.ieee.org/xpls/abs_all.jsp?arnumber=710772

  A Trainable System for Object Detection
CONSTANTINE PAPAGEORGIOU AND TOMASO POGGIO

  http://mesh.brown.edu/engn1610/szeliski/03-imageprocessing.pdf
  http://www.cvc.uab.es/adas/site/userfiles/files/haarfeatures.pdf
  http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=5164257
  [7] Gary B. Huang, Manu Ramesh, Tamara Berg, Erik Learned-Miller, Labeled Faces in the Wild:

A Database for Studying Face Recognition in Unconstrained Environments, University of

Massachusetts, Amherst, Technical Report 07-49, October 2007.

http://vis-www.cs.umass.edu/lfw/index.html
  Improvements in OpenCV’s Viola Jones Algorithm in

Face Detection - Tilted Face Detection
  Explicit Image Detection using YCbCr Space Color Model as Skin Detection
  http://www.merl.com/publications/docs/TR2003-96.pdf
  http://www.csie.ntu.edu.tw/~fuh/personal/FaceDetectionwithOcclusions.pdf
  http://www.iuma.ulpgc.es/camellia/components/com_docman/dl2.php?archive=0&file=Q1ZQUl9jdHJscHRzLnBkZg==
  http://research.ijcaonline.org/volume84/number17/pxc3892949.pdf
  http://download.springer.com/static/pdf/176/bok%253A978-3-642-04697-1.pdf?auth66=1416510815_26bef2b19c6388c13d91fc5400ff9df6&ext=.pdf
  http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=4587539