TY  - JOUR
T1  - On the Present Distribution and Origin of the Calcareous Concretions in Coal Seams, Known as "Coal Balls"
JF  - Philosophical Transactions of the Royal Society of London. Series B, Containing Papers of a Biological Character (1896-1934)
VL  - 200
SP  - 167
EP  - 218
PY  - 1909/01/01/
UR  - http://dx.doi.org/10.1098/rstb.1909.0005
M3  - doi:10.1098/rstb.1909.0005
AU  - Stopes, M.
AU  - Watson, D.
ER  -