Ubong E.U. statistical determination method of cylinder combustion conditions using the cyclic variations of some measurable engine variables / E.U.Ubong, 1991. - 22 p. - Текст : непосредственный.
Ubong E.U. Development of a spark assisted direct injection multifuel diesel engine especially for alcohol fuels / E.U.Ubong, 1989. - 80 p. - Текст : непосредственный.