1RM calculator in ExRx.net (Brzycki’s, Baechle’s and Remedios’ equations to determine 1RM and estimate repetitions at percent of 1RM).
Brzycki, Matt (1998). A Practical Approach To Strength Training. McGraw-Hill.
Baechle TR, Earle RW, Wathen D (2000). Essentials of Strength Training and Conditioning, 2: 395-425.
Remedios R (2007) Men’s Health Power Training, Rodale Inc. 23.