Series D was the first to see all the episodes focus upon a single topic or theme beginning with the series letter, and for each to be given an official title.
The only exceptions to the alphabet system have been the Christmas specials, where the topics are often just of a Yuletide nature and do not necessarily correspond to that series' letter (although greater attempts have been made to do so since series D).
Review the series letter.
Case reports, case series, letters and narrative reviews were excluded.
We also excluded observational studies, case series, letters, commentaries, reviews, and editorials.
The medical literature now includes over 100 published case reports, case series, letters, reviews, and occasional experiments.
Non-randomized or uncontrolled studies, observational studies, case series, letters to the editor, studies with no abstracts or with conference abstracts only were not included.
Non randomized or uncontrolled studies, observational studies, case series, letters to editor, studies with no abstracts or with conference abstracts only were not included.
A suffix letter designates variants of a basic aircraft, with the first model being "A" and subsequent series letters being assigned the next letters of the alphabet (skipping "I" and "O" to avoid confusion with the numbers "1" and "0").
The effectiveness and safety of the treatments are reported mainly in case-reports, case-series, letters to the editor and brief communications.
Publications reporting on case-series (e.g., medical examiner data with no non-events and not including rates, comparative case-series, letters, editorials commentaries, opinion pieces), case reports, reviews, time-series or trend studies were excluded.
