Robert Indiana kept a series of illustrated journals during the late 1950s and 1960s, in which he discusses the development of his work as well as his daily life on Coenties Slip.

Indiana's journal entry for July 4, 1961, includes a sketch of the painting Beating Hearts (Papa). He records adding four dots to the painting (which he began the day before), to celebrate the Fourth of July. He also notes, "did not really think of the significance of 'Papa' until several days later; as it was a strange unconscious tribute to Hemingway [to] [the] surface certainly not my favorite author by a long shot."