https://docs.oracle.com/cd/E88353_01/html/E37846/j0l-3m.html
j0l - man pages section 3: Extended Library Functions, Volume 2
j0 , j0f , j0l , j1 , j1f , j1l , jn , jnf , jnl - Bessel functions of the first kind
man pagesextended librarysectionfunctionsvolume