Knight, J.A. y Sardina, L.J. 2020. An emended and amplified description of Pecopteris apicalis Knight, a fern morphospecies of mid-Stephanian age from NW Spain. Spanish Journal of Palaeontology. 31, 1 (abr. 2020), 95–114. DOI:https://doi.org/10.7203/sjp.31.1.17141.