Avwioro, O.G., Aloamaka, P.C., Ojianya, N.U., Oduola, T. and Ekpo, E.O. 2005. Extracts of Pterocarpus osun as a histological stain for collagen fibres. African Journal of Biotechnology. 4, 5 (Aug. 2005), 460–462. DOI:https://doi.org/10.4314/ajb.v4i5.15122.