Papers of 1836-1837 by Sturm and Liouville on differential equations involved expansions of functions in series and is today well-known as the Sturm-Liouville problem, an eigenvalue problem in second order differential equations.
Papeles ng 1836-1837 by Sturm at Liouville sa kaugalian equation kasangkot expansions ng mga function sa serye at ngayon ay kilala bilang ang Sturm-Liouville problema, isang eigenvalue problema sa pangalawang order kaugalian equation.