Interchanging Hypertexts. - Robert M. Akscyn; Frank G. Halasz; Tim Oren; Victor A. Riley; Lawrence Welch (Hypertext, 1989)

Point-Free Topological Spaces, Functions and Recursive Points: Filter Foundation for Recursive Analysis I. - Iraj Kalantari; Lawrence Welch (Ann. Pure Appl. Log., 1998)

Recursive and Nonextendible Functions over the Reals; Filter Foundation for Recursive Analysis, II. - Iraj Kalantari; Lawrence Welch (Ann. Pure Appl. Log., 1999)