The information in 'Shakespeareana Genealogica' seems to come wholly from the Will of John Shakespeare, of Knowle (1683)

From the IGI:

• married 28 Dec 1714, Knowle, Henry Shakespeare & Sarah Sadler

• married 28 Dec 1714, buried 30 March 1744, Henry Shakespeare, 'of Knowle'

• married 16 July 1739, Knowle, Henry Shakespeare & Elizabeth Crommer

• bapt 30 Jan 1724, died 16 July 1731, Knowle, Samuel, son of Henry & Sarah Shakespeare

See also:

• Packwood Deed - (1611) mentions William Shakespeare, presumably of Packwood

• Packwood Deed - (1601) mentions Francis Shakespeare

• Will of John Shakespeare, of Knowle (1683)