Concentration


 * Marquis, Don (1916), "Concentration" in Hermione and Her Little Group of Serious Thinkers
 * Vivekananda, Swami, "Concentration" [lecture] in The Complete Works of Swami Vivekananda 4
 * Vivekananda, Swami, "Concentration" [notes] in The Complete Works of Swami Vivekananda 6