Surrounding Lord Sankarshana

http://www.harekrsna.com/philosophy/associates/devotees/citraketu.htm

Appearance of 4 Kumaras and Rudra

When Brahma decided to commence the sequence of creation, he first of all created four Kumaras by just having a wish in his mind. They were Sanaka, Sanandana, Sanatana and Sanatkumara.When the four Kumaras came into existence, they were all embodiments of pure qualities. They did not have any sign of negative qualities like laziness, sleep etc. Brahma had created these four Kumaras so that they could help in the process of creation. But they refused when they were ordered by Brahma to do so. So these four Kumaras—kumara means unmarried brahmacaris. Because in the beginning Brahma begot so many sons, and each of them were asked to increase the population. Sanaka, Sananda, Sanatana, they were also requested by their father to increase population, but they refused. They said, “No, we are not going to be entangled in these material affairs. We shall remain kumaras, brahmacaris, and preach the glories of Godhead,” by which Brahma became angry. And while he was angry, from his anger Rudra was produced frm his forehead.

Tilak With Significance

Vedanta Philosophy of Jagadguru Nimbarkacharya

http://www.bhakti-yoga-meditation.com/vedanta-dvaitadvaita.html
Rasa
http://www.sanatansociety.org/yoga_and_meditation/nimbarka_philosophy.htm
Vs Other
http://www.advaitayoga.org/advaitayogaarticles/bhedabheda.html