how to select capacitor for a crystal oscillator
Cp is the input capacitance plus stray capacitance. You can use a few pF (3-5pF) for the value unless something is really strange. 

So, for a crystal rated with a 10pF load, Cl = (10pF-Cp)\$\cdot\$2, so if we use 4pF for Cp, we get 12pF for the load capacitors. 

For the 16pF crystal, Cl = (16-Cp)\$\cdot\$2, so using 4pF for Cp we get 24pF, using 3pF we get 26pF.