**A direct method of solution for the Fokas-Lenells derivative**

**nonlinear Schrödinger equation: II. Dark soliton solutions**

**A direct method of solution for the Fokas-Lenells derivative**

**Nonlinear Schrödinger equation: III. Soliton solutions**

**A direct method of solution for the Fokas-Lenells derivative**

**Nonlinear Schrödinger equation: IV. Soliton solutions**