I am a poet. I applied for ISBN number to Raja Rammohun Roy agency for ISBN, which is the national agency for ISBN in India, on August 22nd, 2016 for my collection of poetry which I am going to publish myself. My real name is SANDEEP DWIVEDI but I write under the pen name (pseudonym) WAHID KASHIWASI. The agency has asked me to prove that this pen name is mine. I've been published in other books and magazines carrying ISBN and ISSN number with the same pen name. How shall I give the proof to the agency that this is my pen name? Please help me as my date of publication is close but I haven't been provided with ISBN.