Cita APA (7th ed.)
Stebbins, George Ledyard, jr: The American Species of Crepis.
Cita Chicago (17th ed.)
Stebbins, George Ledyard, Jr: The American Species of Crepis.
Cita MLA (9th ed.)
Stebbins, George Ledyard, Jr: The American Species of Crepis.
Atenció: Aquestes cites poden no estar 100% correctes.