John XXIII, P. (1960). On the use of leisure time: Letter to Social Week of Italian Catholics, September 20, 1959. N.C.W.C..
Chicago-referens (17:e uppl.)John XXIII, Pope. On the Use of Leisure Time: Letter to Social Week of Italian Catholics, September 20, 1959. Washington, D.C.: N.C.W.C., 1960.
MLA-referens (8:e uppl.)John XXIII, Pope. On the Use of Leisure Time: Letter to Social Week of Italian Catholics, September 20, 1959. N.C.W.C., 1960.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.