How to determine the starting values for linear multistep methods? I am so confused with how to determine the starting values for linear multistep methods. 
I have searched the wiki page for linear multistep method. And it says that for Two-step Adams–Bashforth, the starting values are just got by Euler's method. 
I have also found this page. And the case is that the exact solution is already known. 
So my question is that: for common cases, how to determine the starting values?

For AB2 any first order one-step method can be applied to generate the missing starting value. But it is worth to mention that any second order one-step method would result in a slightly better result.
Generally, for an n-th order LMM an (n-1)-th order one-step method can be applied to generate the missing starting values, although any n-th order one-step method would result in a slightly better result.
