19 
    
    Emmy E. Werner and Ruth S. Smith, Vulnerable but Invincible: A Study of Resilient Children (New York: McGraw-Hill, 1982).
                20 
    
    Lois B. Murphy and Alice E. Moriarty, Vulnerability, Coping and Growth from Infancy to Adolescence (Oxford, UK: Yale University Press, 1976).
                21 
    
    Manfred Bleuler, The Schizophrenic Disorders: Long-Term Patient and Family Studies (New Haven, CT: Yale University Press, 1978).
                22 
    
    Elwyn J. Anthony and Bertram J. Cohler, eds., The Invulnerable Child (New York: Guilford, 1987); see p. ix.
                23 
    
    Norman Garmezy, «Vulnerability Research and the Issue of Primary Prevention», American Journal of Orthopsychiatry 41, no. 1 (1971): 101–116; see p. 114.