S: UNESCO – http://www.unesco.org/education/efa/global_co/working_group/pres10_caribbean_community.shtml (last access: March 2013); NAVARRO p. 312.
N: By backwardness is com monly meant the effects of delayed progress or development in the growing child. Backwardness may be either physical or mental. It is, however, chiefly in mental backwardness that scientific interest has centred. Apart from exceptional cases of a medical or pathological nature such as cretinism or deferred puberty, physical immaturity has mainly been studied because of its apparent influence on the expansion of the mind. Quite recently efforts have been made to find a precise measure of physical backwardness—based, for example, on height, weight, or X-ray photographs of the structure of the bones. But these have been largely undertaken to compare anatomical growth and physiological development with advance in mental capacity.
S: http://gluedideas.com/Encyclopedia-Britannica-Volume-2-Annu-Baltic/Backward-Children.html (last access: 2 October 2015)