Complex sentence: The "Encyclopædia Britannica" Eleventh Edition (1910--1911) is a 29-volume reference work, an edition of the "Encyclopædia Britannica"' s transition from a British to an American publication.
Split into simpler sentences: The "Encyclopædia Britannica" Eleventh Edition (1910--1911) is a 29-volume reference work, an edition of the "Encyclopædia Britannica"'. It was developed during the encyclopaedia's transition from a British to an American publication.