Sita's Sister by Kavita Kane.
Though Urmila, Sita's younger sister, Lakshman's wife sacrificed and suffered a lot but none paid much attention to this character. So here is the book through which you would be able to know her more deeply. Her joy, anger, pride, brevary, care for others and deep love and respect for Lakshman...
You will experience much more. So read it atleast once. I have written a blog about this book ( Retelling of the Ramayana but from a different perspective), you can check it on medium for more details.
Thank you.