U. S. Government Accountability Office, GAO-18–258, March 2018.
51
Marek Spinka et al. (2001).
52
Dieter Leyk et al. (2007).
53
Kevin MacDonald and Ross Parke (1986); Michael Lamb and David Oppenheim (1989), p. 13.
54
Toledo Blade, November 13, 1987; Anthony Volk (2009).
55
Rebecca Herman et al. (2003).
56
Lynn Fairbanks (1990).
57
Elizabeth Warren, April 25, 2019, twitter.com/ewarren.
58
Cathy Hayes (1951); Robert Mitchell (2002).
59
John Money et al. (1955).
60