formative assessment in grade 4

I'm looking for articles related to the use of formative assessment; particularly the use of formative assessment by teachers in order to plan for greater learning of students.   I want to improve the way I assess within my classroom, and how I use the results, with the hope of increasing the value of my instruction.  I want my lessons to be building on knowledge and filling in the gaps in understanding, not just adding information that leads to students who  "just don't get it."   Any recommendations for articles, links to them, etc. will be appreciated. Thank you!