MLA

Walter, Richard, 1716?-1785. A voyage round the world in the years MDCCXL, I, II, III, IV : by George Anson, Esq; now Lord Anson, commander in chief of a squadron of His Majesty's ships, sent upon an expedition to the South-Seas / compiled from his papers and materials by Richard Wal. MDCCXLIX [1749]. https://collections.library.yale.edu/catalog/15307260.

APA, 6th edition

Walter, Richard, 1716?-1785. (MDCCXLIX [1749])[A voyage round the world in the years MDCCXL, I, II, III, IV : by George Anson, Esq; now Lord Anson, commander in chief of a squadron of His Majesty's ships, sent upon an expedition to the South-Seas / compiled from his papers and materials by Richard Wal]. https://collections.library.yale.edu/catalog/15307260.