solved Guidelines for Preparation of an Informative Abstract An abstract is

Guidelines for Preparation of an Informative Abstract
An abstract is a condensed version of a longer piece of writing that highlights the major points covered, concisely describes the content and scope of the writing, and reviews the writing’s contents in abbreviated form.
An informative abstract is an abbreviated version of a journal article- no longer than 1 single-spaced page, or approximately 10% of the original article. Abstracts should contain enough detail to allow the reader to understand and use the information. 
Reliable professional journals are the preferred souce for selection of articles for abstracts. The following are some guidelines for writing an informative abstract:

Cite bibliographic information at the top of the page. Carefully follow this example:

Misra, S., Daly, B., Dunne, S., Millar, B., Packer, M. & Asimakopoulou, K. (2013). Dentist-patient communication: What do patients and dentists remember following a consultation? Implications for patient compliance. Patient Prefer Adherence, 7(1), 543-549. http://doi: 10.2147/PPA.S43255

Note that the bibliographic citation is not double spaced (as in APA style)
Also, do not use “hanging indent”
After the citation, double space and begin your abstract
Abstracts are single-spaced, and generally no longer than 1 page