(en) John Frederick Dorman, The Prestons of Smithfield and Greenfield in Virginia: descendants of John and Elizabeth (Patton) Preston through five generations, Filson Club, (ISBN9780960107216, lire en ligne), 113
(en) Charles Henry Bell, The Bench and Bar of New Hampshire: Including Biographical Notices of Deceased Judges of the Highest Court, and Lawyers of the Province and State, and a List of Names of Those Now Living, Houghton, Mifflin, (lire en ligne), 764
« DR. S. D. BRECKINRIDGE, GYNECOLOGIST, WAS 59; Kentucky Practitioner, Former National Fencing Champion », The New York Times, (lire en ligne, consulté le )
« Col. Henry Breckinridge Dies; Ex-Assistant Secretary of War; Wilson Cabinet Aide at 27-- Was Intermediary in the Lindbergh Kidnapping », nytimes, (lire en ligne, consulté le )
« BOOM IS STARTED FOR BRECKINRIDGE; Aide to Wilson Now Seeking Senatorial Nomination on Independent Ticket. », nytimes, (lire en ligne, consulté le )
Gruin, « BRECKINRIDGE OUTLINES HIS POLITICAL BELIEFS; Candidate for the Senate, He Declares His Stand for Recovery 'Along Constitutional Lines' », nytimes, (lire en ligne, consulté le )
Breckinbridge, « TAMMANY IN WASHINGTON.; Col. Breckinridge Sees National Spoils System as an Issue. », nytimes, (lire en ligne, consulté le )
« ROOSEVELT IS CRITICIZED; Breckinridge Says He Has Lost 'Moral Right' to Jersey Support. », The New York Times, (lire en ligne, consulté le )
« Breckinridge to File as Foe of New Deal In the Maryland Presidential Primary », The New York Times, (lire en ligne, consulté le )
« ROOSEVELT CARRIES MARYLAND BY 5 TO 1; Returns Show Breckinridge Trailing Everywhere in Preferential Ballot. POLL INSTRUCTS 16 VOTES Jackson's Candidate for House Is Victor Over Curran Rival in Baltimore. », The New York Times, (lire en ligne, consulté le )