There are a number of parallels between this episode and Samuel Taylor Coleridge's poem 'Rime of the Ancient Mariner', which was written in 1797-1798.
The book that Claire quoted while on the deck with Jamie while staring at the moon is 'Goodnight Moon' by Margaret Wise Brown. The book was first published Sep 03, 1947. This was 14 months before Brianna was born, as stated in Dragonfly in Amber (2016).