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.
I get asked that a lot. There are many differences as well as similarities between the two. Often looking very similar, both folding cartons and rigid boxes are indeed boxes used for packaging and both are made of paperboard. Paperboard is basically thick paper that is sturdy enough to be used for packaging.