Leonard Euler’s discussion of volume 1 of his Integral Calculus concerning the integration of logarithmic and exponential functions on page 121 of Integral Calculus, vol. 1 (1768). Note that Euler used lx to represent what we write as ln(x).
The complete Integral Calculus in three volumes appeared in the interval 1768 – 1770. This was the first complete textbook published on the integral calculus.