The World on Mercator's Projection: By David H. Burr. Showing the different routes to California and distance by each. Routes of different Navigators, route of the contemplated Pacific R.Road. Distances to China, Europe, etc.
MLA
The World on Mercator's Projection: By David H. Burr. Showing the Different Routes to California and Distance by Each. Routes of Different Navigators, Route of the Contemplated Pacific R.Road. Distances to China, Europe, Etc. J. Haven, 1850. https://collections.library.yale.edu/catalog/15234624.
APA, 6th edition
The World on Mercator's Projection: By David H. Burr. Showing the different routes to California and distance by each. Routes of different Navigators, route of the contemplated Pacific R.Road. Distances to China, Europe, etc. (1850). [Maps]. J. Haven, https://collections.library.yale.edu/catalog/15234624.