meaning of parameters for scipy.spectial.pro_ang1

I'm trying to compare:
http://docs.scipy.org/doc/scipy/reference/generated/scipy.special.pro_ang1.html#scipy.special.pro_ang1

which lists 4 parameters:
(m, n, c, x)

with this reference:

https://www.researchgate.net/publication/223606627_Prolate_spheroidal_wave_functions_an_introduction_to_the_Slepian_series_and_its_properties

which refers to 4 parameters (see section 2):
The continuous time parameter t, the order,n, of the function, the interval
on which the function is known, t0, and the bandwidth parameter c. The
bandwidth parameter is given by c= t0?, (3) where? is the finite bandwidth
or cutoff frequency of?n(t) of a given ordern.

Unfortunately the scipy doc doesn't give a description of it's parameters or
any reference.

Sorry, posted to wrong list