@article{BG92,
author = {R. Barbuti and R. Giacobazzi},
title = {A {B}ottom-up {P}olymorphic {T}ype {I}nference in {L}ogic 
	{P}rogramming},
journal = "Science of Computer Programming",
year = {1992},
volume = "19",
number = "3",
pages = {281-313}}