Cita APA (7a ed.)
Throop Purdy Helen. (1923). SAN FRANCISCO AS IT WAS AS IT IS AND HOW TO SEE IT.
Cita estilo Chicago (17a ed.)
Throop Purdy Helen. SAN FRANCISCO AS IT WAS AS IT IS AND HOW TO SEE IT. 1923.
Cita MLA (9a ed.)
Throop Purdy Helen. SAN FRANCISCO AS IT WAS AS IT IS AND HOW TO SEE IT. 1923.
Precaución: Estas citas no son 100% exactas.