I have recently posted a very interesting academic study on Ulster marriage patterns and traditions that used Lisbellaw and surrounding townlands as the study area. It is an excellent survey of Fermanagh families from the area. It has excellent information that can be applied across Ulster. I found it in some obscure book some time ago. I have tried to find the professor who authored the article but she has retired. The book was published in India. There is also an article specific to the Black family of Belfast, originally of Cowall, Scotland at my web site. http://www.geocities.com/Paris/Musee/7023/