APA

Simkin T., Howard K. A., . (1968). The 1968 collapse of Fernandina caldera, Galápagos Islands. : .

Chicago

Simkin Tom, Howard Keith A, . 1968. The 1968 collapse of Fernandina caldera, Galápagos Islands. : .

Harvard

Simkin T., Howard K. A., . (1968). The 1968 collapse of Fernandina caldera, Galápagos Islands. : .

MLA

Simkin Tom, Howard Keith A, . The 1968 collapse of Fernandina caldera, Galápagos Islands. : . 1968.