TY - GEN AU - George Keinath C2 - , National Institute of Standards and Technology, Gaithersburg, MD DA - 1959-01-01 05:01:00 DO - https://doi.org/10.6028/NBS.CIRC.601 LA - en PB - , National Institute of Standards and Technology, Gaithersburg, MD PY - 1959 TI - Circular of the Bureau of Standards no. 601::recorder survey- recording surfaces and marking methods ER -