Tag: Observer Voice Julius Richard Petri

31 May: Remembering Julius Richard Petri on Birthday

Julius Richard Petri (31 May 1852 – 20 December 1921) was a

OV Digital Desk

20 December: Tribute to Julius Richard Petri

Julius Richard Petri (31 May 1852 – 20 December 1921) was a

OV Digital Desk