Two or More Works by the Same Author in the Same Year: If you have two sources by the same author in the same year, use lower-case letters (a, b, c) with the year to order the entries in the reference list. Use the lower-case letters with the year in the in-text citation.
The next type of board is the longboard or malibu (mal). The main difference in design is that the nose of the longboard is rounded. Other than that there is no real difference, though shortboards tend to have three fins and longboards tend to have a single fin.
We're talking about the four primary types of surfboard designs. The first is the shortboard, also known as the thruster. This is the type of board that is pictured below. It's a board used to perform quick maneuvers on waves and is the most popular type of surfboard design. The size of these shortboards is generally from around 5'8'' to 6'10''.