three modules are monodirectionally (i'm not sure if this is a word) associated by USE statements i.e. MODULE A ... contains SUBROUTINE mod_a_1 ( ) .. END SUBROUTINE mod_a_1 ... END MODULE A MODULE B_1 use A ... END MODULE B_1 MODULE B_2 use A ... END MODULE B_2 MODULE C use B_1 use B_2 ... END MODULE C what are the implications if B_1 and B_2 use subsets of A via the ONLY keyword. ?? Thanks in advance, Colin.