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.
Corrugated fiberboard or combined board has two main components: the liner and the medium. Both are made of a special kind of heavy paper called containerboard. Linerboard is the flat facing that adheres to the medium.