ABSTRACT: Center, type and underline Abstract heading, capitalizing the first letter. A double-space should separate the heading from the abstract text. Indent approximately 1/2 inch (13 mm) from both left and right margins for typing the abstract. The abstract should be approximately 50 to 70 words in length. It should be factual and contain the main results and conclusions of the paper. It should be intelligible to the reader without reference to the body of the paper and be suitable for reproduction by abstracting services. Introduction to the text (without a heading) should begin two spaces below the abstract using full margins.