@incollection {D:two-enrich,
	title = {Two semantically motivated enrichments of relevant logics},
	booktitle = {Essays in Philosophical Logic},
	year = {1987},
	pages = {65{\textendash}74},
	publisher = {Jagiellonian University Press},
	author = {Batens, Diderik},
	editor = {Perzanowski, Jerzy}
}
