Continuous forms for making indexes

A continuous form for making one or more index sheets comprising an elongated strip of material perforated along a first line or a first set of lines transverse to the length of the strip, so that when the strip is split along the first line or first set of lines, a plurality of individual sheets are obtained, wherein at least one sheet is perforated along a second line which is so positioned on such sheet that when said at least one sheet is split along the second line, an index sheet of predetermined shape is obtained, said second line being adjacent and substantially parallel to one side of such sheet, said second line of perforation traversing the length or width of such sheet except for a predetermined portion, said second line of perforation being connected to such one side by one or more additional lines of perforation near the edges of the portion, so that when such sheet is split along said second line and said additional lines of perforation, an index sheet with said portion forming an index tab will result.