Hanrahan's paper, link above, is one of the true "classics".
Implementing a configuration which was actually disclosed a quarter-century earlier by Habermann, IIRC, its self-starting characteristic is fine for small RPCs, and also for small load motors, too, most particularly those which are implicitly easy to start, such as centrifugal coolant pumps.
Richarson's paper, available elsewhere in this Forum, and which also predates Hanrahan's, contains very complete performance curves, much more complete than Hanrahan's.
Not withstanding that observation, Hanrahan's paper is a definite "must read", and should be read first, before other, less readable sources are consulted.