On a Steady-State Potential Flow through a Conical Pipe with a Circular Aperture J. BazerS. Karp Indiana University Mathematics Journal 1956 text pdf 10.1512/iumj.1956.5.55010 10.1512/iumj.1956.5.55010 en Indiana Univ. Math. J. 5 (1956) 277 - 322 state-of-the-art mathematics http://iumj.org/access/