OM System Olympus OM-1: Pocket Guide: Buttons, Dials, Settings, Modes, and Shooting Tips (The Pocket Guide Series for Photographers, 25) [Nook, Rocky]
The Online Photographer: The Goldilocks 'Just Right' Camera
Sony a7 IV: Pocket Guide by Rocky Nook - Ebook
Olympus OM-D E-M1X Micro Four Thirds Mirrorless Camera Test & Review
Olympus OM-1 Guide – Phil Norton Photography
OM Systems OM-1: Best Settings for Beginners - Step by Step Tutorial ep.371
Is anyone exploring the Olympus OM-1 for birds and wildlife?, Page 10
How I Set Up the OM System OM-1 for Nature Photography – Martin Belan
Olympus OM-D E-M5 Mark III — The Complete Guide and Review, by Anonymous Keyboard
OM System OM-5 Review
Rocky Nook's Pocket Guides are handy - ultra-portable - and quick to reference to help you get the shot when you're out and about.
OM System Olympus OM-1: Pocket Guide: Buttons, Dials, Settings, Modes, and Shooting Tips [Book]
OM SYSTEM OM-1 User's Guide by Ken Rockwell
Rocky Nook Photography Techniques Books in Photography Books
Olympus Essential Camera Handbook
How I Set Up the OM System OM-1 for Nature Photography – Martin Belan
The OM-d E-m1 Mark III From Olympus