Sources are very important to good Gen research. As Webmaster, I have seen several different web sites that contain birth records for a particular one of my ancestors (not a McAllister). On at least three of them, the same typo is included and not a single one of the sites offers any sources. This means that at least two sites are simply copying from one of them. Worse still, none of them say where they got their data so there is no real proof that the dates are real. Now I do not for one minute believe they just made up the data, but the fact remains that when there are no sources, there is no way for future generations to verify the data without re-doing the research. This is a real pity and a collossal waste of time and resources.
Much of the information in your family tree was probably collected by speaking with relatives. For this reason, complete documentation of your family information is difficult. However, if you did get your information from verbal sources, go ahead and say so. It is a perfectly valid source. Always record those sources, even if it is a conversation with Aunt Tillie. If the source was an old family Bible, say so and, if possible, scan the page and copyright page. Wherever you get your information, be sure to record it and keep that Source record with the rest of your genealogical data.
You can also check the genealogy books at your local library, or ask a local genealogy society for more information. The potential for data errors exists, even in the most careful genealogist's family tree. By collecting and listing sources, future generations of researchers can easily verify your work or compare sources in the event of discrepancy which is, unfortunately, common in genealogy.
We look forward to hearing from you,