DOE:10.18520/cs/v111/i1/53-75
DOE:10.18520/cs/v111/i1/93-100
DOE:10.18520/cs/v111/i1/101-108
DOE:10.18520/cs/v111/i1/109-116
DOE:10.18520/cs/v111/i1/132-140