Kirk, W.D.J., & Howes, F.N. 2012 Plants for Bees
Miller-Klein, Jan. 2010 Gardening for Butterflies, Bees and other beneficial insects
O'Toole, Christopher. 2013 Bees: A Natural History
Peeters T.M.J. et al. 2012 De Nederlandse Bijen
Kirk, W.D.J., & Howes, F.N. 2012 Plants for Bees
Miller-Klein, Jan. 2010 Gardening for Butterflies, Bees and other beneficial insects
O'Toole, Christopher. 2013 Bees: A Natural History
Peeters T.M.J. et al. 2012 De Nederlandse Bijen