Taiwan bark paintings .. Where can I get more info?

Have 2 very large ones, painted with primitive bamboo brush and bark sap. Where can I get more info on them ? Where can I find the value? I don't have photos presently , but, will have some in a week or two. I will eventually look to sell them or trade for Native American stone relics from New York, Pa., N.J. or esp. Maine, VT, NH, Ct., or M. esp. from old collections with great history and provenance info... Thanks for any info !! Ken in N.J.