Polivka, Z: Potential hypnotics and anxiolytics in the 4h-s-triazolo/4,3-a/-1,4-benzodiazepine series: 8-chloro-6-(2-chlorophenyl)-1-/4-(2-methoxyethyl(-piperazino/-4h-s-triazolo/4,3-a/-1,4-benzodiazepine and some related compounds