Ok, I still can't post replies just yet, but I've found some papers about the model described in the article "A Relational Model of Programming."
"Teaching Design of Objects and Classes through a Relational Model of Programming" http://citeseer.nj.nec.com/473768.html
"On Composing Problems and Parallel Programs" http://citeseer.nj.nec.com/81112.html (the notation is very heavy and unstructured in the above paper; maybe the authors were trying to meet page count limitations?)
"Proving the Temporal Properties of the Unique World" http://citeseer.nj.nec.com/ath99proving.html