The PDF documents were converted into machine-readable format using the IBM Deep Search platform . The details of the PDF conversion pipeline are explained in related publications and summarized here. Deep Search uses multiple neural networks which are trained to extract bounding boxes or PDF cells generated by PDF printing commands. Next, the cells are classified into several labels including title, author, abstract, affiliation, subtitle, text, formula, table, image, caption, footnote, citation, keyword, etc. The information contained in the PDF cells and their predicted labels are jointly assembled in a machinereadable format. The final machine-readable document engenders multiple downstream use-cases like question-answering from documents , universal information extraction 2 , or NER as in the present case.