@article {MR1222186,
	title = {The decomposability of operators relative to two subspaces},
	journal = {Studia Math.},
	volume = {105},
	number = {1},
	year = {1993},
	pages = {25{\textendash}36},
	issn = {0039-3223},
	url = {https://doi.org/10.4064/sm-105-1-25-36},
	author = {Katavolos, A. and Lambrou, M. S. and Longstaff, W. E.}
}
