Amazon.com: Digital Camera External Microphone Compatible with Olympus Pen E-PL9 Mirrorless Digital Camera, XM-AD2 Dual Channel XLR-Mini Audio Adapter for DSLR's, Camcorders and Pro Video Cameras : Electronics
Olympus SEMA-1 Microphone Adapter Set 147592 B&H Photo Video
Olympus ME30W 2-Channel Professional Microphone Kit