Mobility International USA article: Should You Bring a Manual or Power Wheelchair? Discusses the pros and cons of manual and power wheelchairs in different situations with different terrains and offers advice about suitability of shares in different situations as well as advice on maintenance and charging. There is also a list of 13 links to wheelchair retailers, third wheel retailers and all-terrain wheelchairs.https://www.miusa.org/resource/tipsheet/choosingchairs