When HarperCollins decided to create a series of spin-off books featuring various extended family members of Laura Ingalls Wilder, they made each author assume a pseudonym that began Wil- so that they would appear besides Laura on bookshop shelves. Maria D. Wilkes was really Maria T. DiVencenzo. DiVencenzo is now one of a group of partners who have set up their own publishing company, Winter Lake Press. Lots of news and info on the web site.
She has released a Christmas book (unrelated to Laura).
Sarah S. Uthoff, Trundle Bed Tales