Links
[1] https://www.hootsgo.org/?q=node/6555
[2] http://speedmath.blogspot.com/2013/03/paravartya-yojayet.html
[3] https://bineeshthomas.wordpress.com/2011/05/25/sutra-4-paraavartya-yojayet-transpose-and-adjust/
[4] http://mathlearners.com/vedic-mathematics/division-in-vedic-mathematics/paravartya/
[5] http://blogannath.blogspot.in/2009/09/vedic-mathematics-lesson-18-division-by.html