(subclass Coal Mineral) | Geography.kif 2017-2017 | Coal is a subclass of mineral |
(subclass Coal FossilFuel) | Geography.kif 2018-2018 | Coal is a subclass of fossil fuel |
(subclass Coal Rock) | Geography.kif 2019-2019 | Coal is a subclass of rock |
(subclass BrownCoal Coal) | Geography.kif 2003-2003 | Brown coal is a subclass of coal |