中国科学院数学与系统科学研究院期刊网
AMS
On Second Order Degree of Graphs
Gabriela ARAUJO-PARDO, Camino BALBUENA, Mika OLSEN, Pilar VALENCIA
Acta Mathematica Sinica . 2012, (1): 171 -182 .  DOI: 10.1007/s10114-012-9343-8