You may wish to have a reference to a paper or collection of papers presented at a conference or seminar. These are generally known as conference papers or proceedings.
These are the details you will need to construct a reference for a conference paper, the punctuation marks at the end of each element being those you should use to put the reference together.
Anderson JC. Current Status of Chorion Villus Biopsy. In: Tudenhope D, Chenoweth J, editors. Proceedings of the Fourth Congress of the Australian Perinatal Society; 1986 Sept. 3-6; Brisbane, Queensland: Australian Perinatal Society; 1987. p. 190-6.