“…The construction of such designs may be necessary when a BIB design with the corresponding v and b is not available, or when the blocks are naturally not of equal size (see Example 3.1.2). There are several methods of constructing such VB designs, for example, see Agrawal (1963), John (1964), Murty and Das (1967), Das and Rao (1968), Dey (1970), Kulshreshtha, Dey and Saha (1972), Hedayat and Federer (1974), Kageyama (1976dKageyama ( , 1988aKageyama ( , 1988b, Khatri (1982), Gupta and Jones (1983), Kumar (1984, 1986a), Mukerjee and Kageyama (1985), Jones, Sinha and Kageyama (1987), Pal and Pal (1988), Sinha (1988Sinha ( , 1989Sinha ( , 1990, Sinha and Jones (1988), Calvin and Sinha (1989), Hedayat and Stufken (1989), Gupta and Kageyama (1992), Ghosh, Joshi and Kageyama (1993), andKageyama (1996, 1997). Most of these methods utilize BIB designs and GD designs in their constructions.…”