For 2019, the Vikings have following referees available:

National Level
Daniel Triebsch / Nico Piveteau
Maddy Hazelton / Inga Zuzevičiūtė

Regional Level
Harry Ireland / Todd Anderson
Miguel Aizpuru / Paul Ireland
Bridget Ireland / Lizzie Boyle

Local Level
Liam Madigan / Laurin Schoppe

Handball Rules
Rules of the game (here as a pdf)
Simplified Handball rules for beginners (here as a pdf)
Handball rules wonderfully explained in a short youtube clip (here)