A book worth dipping into is

'Living Downstream, 

An Ecologist Looks at Cancer

and the 'Environment' 

by Sandra Steingraber,

This was published by in 1997 by Addison-Wesley.

Although she covers all types of cancer

there are useful references to lymphomas.

She, too, refers to clusters in farming areas

and the use of herbicides and insecticides

and mentions organophosphates

including Agent Orange

to which so many Vietnam veterans were exposed.

She points out that the heavy use 

of herbicides and insecticides in the home and garden 

have played a malignant role in the increase of lymphomas.

Also she highlights the dangers of substances used in certain industries

 mentioning benzene, perchloroethylene used in dry-cleaning and PCBs

She provides an extensive indexed reading list

but unfortunately no reference to on-line sources.