BibTex format
@article{FERREIRA:1994:10.1006/jmaa.1994.1366,
author = {FERREIRA, MMA and VINTER, RB},
doi = {10.1006/jmaa.1994.1366},
journal = {JOURNAL OF MATHEMATICAL ANALYSIS AND APPLICATIONS},
pages = {438--467},
title = {WHEN IS THE MAXIMUM PRINCIPLE FOR STATE CONSTRAINED PROBLEMS NONDEGENERATE},
url = {http://dx.doi.org/10.1006/jmaa.1994.1366},
volume = {187},
year = {1994}
}