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.

1. Author's or authors' surname(s) followed by first name or initials.
2. Title of the paper.
3. In: (to indicate that the next element is the collection of papers from the conference)
4. Editor's or editors' surname (s) followed by initials or first name if the paper appears in an edited book.
5. Title of the conference;
6. Date of conference;
7. Place of publication:
8. Publisher's name;
9. Year of publication.
10. Page numbers.

For example
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.