Then, in "the summer or early fall of 1969. [fact]
Then, in "the summer or early fall of 1969," Scholes told Black of his efforts, and Black described the different approach he had taken, in particular showing Scholes the Taylor-series expansion of the warrant price that echoed his work with Treynor (Scholes 1998, p. 480).
Donald MacKenzie, An Engine, Not a Camera, loc. 578